SK285166B6 - Method for producing a container having a pressure compensation opening, and container produced according to said method - Google Patents

Abstract

The invention relates to a method for producing a container (1) that comprises an outer container (2), an inner pouch (34) disposed therein, and a pressure compensation opening (10) provided in the outer container (2). The invention also relates to a container (1) produced by the inventive method. A preform consisting of two coaxial tubes is produced by a coextrusion blow-molding method using a blow mold, whereby a bottom seam (5) is produced that protrudes outwardly. The aim of the invention is to provide a method by which a container (1) is provided with a pressure compensation opening (10) in the outer container (2) without impairing the tightness of the container (1) while reducing the reject rate and increasing productivity. To this end, the bottom seam (5) is partially cut away and a force is applied on the preform that still has a temperature of 40 DEG C to 70 DEG C, said force acting in the direction of the seam. Said force breaks up the bottom seam (5) and plastically deforms it so that a pressure compensation opening (10) is formed in the bottom area (4).

Description

The invention relates to a method for manufacturing a container having an opening in a container, comprising a substantially rigid outer container and an inner bag therein, which is in contact with the contents of said container, which consist of different thermoplastics which are not connected to each other; a pressure equalization placed in the outer container which equalizes the pressure difference between the outer container and the inner bag, wherein the preform comprising two coaxial tubes having sufficient length to produce the container is first produced by coextrusion between the open halves of the blow mold, the blow mold is closed thereby forming an outwardly projecting base seam, wherein the excess material in the base region of the container to be produced is extruded out in such a way that the material of the outer container in contact with the seam region is welded together, the tube forming the inner the bag attaches axially is fixed and welded between the wall portions of the outer container, and the inner bag is subjected to pressure such that the walls of the preform will abut the outlines of the blow mold from the inside.

Further, the invention relates to a container, preferably manufactured according to this method, with an opening in the container which substantially comprises a rigid outer container and an inner bag disposed therein in contact with the contents of said container.

BACKGROUND OF THE INVENTION

A method of the type considered is described in WO 99/11451. A feature of this method is that the pressure equalization port through which the pressure difference existing between the outer container and the inner bag is equalized is preferably configured as a lenticular or ellipsoid opening in the outer container, which opening is formed by cutting off a section after the current molding process. walls of the outer container by means of a cutting tool.

This means that the outer wall adjacent to the very thin, flexible inner bag must be completely cut off, at least in a very small area, without causing any damage to the inner bag. The processing of the outer container brings about the necessary contact between the cutting tool and the inner bag. Essentially, the most important quality features of the method and of the container made according to this method cannot be realized to the same extent at the same time. In this method or container they diverge. On the one hand, it must be possible to achieve a pressure equalization between the outer container and the inner bag, which is necessary due to the reduction in the volume of the inner bag associated with the removal of the contents of the container. On the other hand, the container must be completely closed, i. j. damage to the inner bag at all costs should be avoided, otherwise the container would be unusable. The difficulty of satisfactorily accomplishing both tasks is discussed in WO 99/11451. For example, it is argued that due to the tolerances in the wall thickness of the outer container that occur during manufacture, and the wall thickness can vary between 1 and 1.5 mm, in practice the cutting depth must be adjusted to ensure that the cutting process will be an opening that actually penetrates the outer container. In any case, damage to the inner bag cannot be excluded. Therefore, WO 99/11451 describes preferred process steps and tools that should be used to minimize the risk of damage to the inner bag.

A further disadvantage of the described process is that the configuration of the pressure equalization opening does not take place immediately after the molding process. The cutting step in the process cannot be carried out on a plastic blow molding machine and especially not when the blow mold is closed. The additional processing machine or tools required for the proposed cutting method and the work steps that would be necessary lead to increased costs and reduced productivity.

In addition, it may be desirable to attach a pump or sprayer to the opening of the container of the type in question through which the material in the inner bag of the container is filled or removed. Depending on the configuration of the pump or sprayer used, the pressure equalization port may be partially or completely closed by a suitable pump or sprayer. In other words, no adapter can be attached to the vessel under consideration, rather it is necessary to take into account the particular position of the pressure equalization port in the respective embodiment. Particularly unsuitable positions for the wall opening in this case are the positions in the bending regions and in the surface area of the container shell. The most suitable position for the wall opening, the base of the container, is not explicitly mentioned.

EP-A-182 094 discloses a method which goes beyond the previously described methods. According to this document, the production of the aeration opening is carried out without a cutting tool. The aeration orifice is produced either by heat shrinking or by opening with a blow molding tool. However, this method also involves additional work steps, which means a reduction in productivity.

On this basis, it is an object of the invention to provide a method by which a pressure equalization port located in an external container of the container under consideration can be configured without compromising the integrity of the container, which method should have only a minimum number of steps and less expensive than the method used in the container. while at the same time allowing for lower losses and higher productivity.

In addition, a container should be provided that has a pressure equalization opening in its outer container without damaging the inner bag during cutting of the opening, and which has no other disadvantages.

SUMMARY OF THE INVENTION

This object is achieved by the method according to the invention, which is characterized in that, when closing the blow mold and thus forming the base seam, the seam of the inner bag is at least partially fixed axially in the seam of the outer receptacle and at least one pressure equalization hole is formed by the base seam is cut at least partially but preferably not completely after molding, so that at least a portion of the seam of the inner bag remains fixed in the seam of the outer container, and then a radial force acting in the seam direction is introduced into the base region in such a way as to wherein the preforming temperature is between 40 ° C and 70 ° C when cutting the base seam and the outer container is still plastically deformable to some extent, so that a force that is not neutralized by elastic regeneration results in permanent deformation.

The walls of the outer container and inner bag, which contain different thermoplastics, are generally not welded. Due to the force exerted during the extrusion of excess material through the half of the blow mold,

In any case, the inner wall of the inner bag and the outer wall of the outer container are welded together. In addition, adhesion occurs in the areas of the base seam between the walls of the inner bag and the outer container. This is an essential advantage of this method with respect to the fixation of the inner bag in the base region. Here, the adhesion is such that when the base seam of the outer container splits, one of the two sides of the seam remains attached to the seam of the inner bag, while the other side of the seam of the outer container does not remain attached to the inner bag. In this way, axial fixation of the inner container is guaranteed despite this splitting, even in embodiments where the seam of the outer container is split along its entire length. Fixing the inner bag is of particular importance in cases where a cannula is inserted into the container and detaching the inner bag from the base area could result in damage or blockage to the cannula. Damage to the inner bag is avoided in the method of the invention because the seam is only partially cut off and therefore the inner bag is tightly closed even after the cutting process has been performed on the remaining seam of the inner bag. In contrast to the prior art method, the configuration of the pressure equalization hole is not created directly by the cutting process, but rather by applying force and splitting the seam. The size of the losses is minimized.

Preferred embodiments of the method are those in which the axial force exerted substantially parallel to the longitudinal οδού of the container is shortly introduced after at least partially splitting the base seam and before introducing the radial force so that the base seam is at least partially split so that it is opened.

The axially applied force primarily serves to open the base seam by splitting, while the effect or purpose of the radially applied force can be seen as a permanent deformation of the base seam. Nevertheless, both forces are involved both in the deformation of the container, in particular the base region, and in the cleavage opening process, with the cleavage opening process being preferred at one point and the deformation at another point.

Preference is given to methods in which the axial force is introduced in the form of an impact.

Preference is given to process variants in which the production of the container is carried out without bending the seam in the form of a compressed seam.

This method is preferably performed such that when the base seam is split, the material constituting the inner bag remains adhered on one side of the base seam to the outer container and at the ends of the base seam while maintaining axial fixation. In this case, the pressure equalization opening between the inner bag and the outer container is located on the opposite side of the base seam.

A method is preferred in which the base seam of the outer container is only partially split and the seam of the inner bag is fixed by a portion of the base seam of the outer container that is not split.

In a preferred method, the base seam is cut off and the force that opens and permanently deforms the outer container is developed in one operation. This can be translated so that the cutting tool and the seam splitting tool work together and almost simultaneously in one work step. A very efficient variant of the method assumes that cutting the base seam and exerting a force that opens and permanently deforms the outer container is realized not only in one working step, but also with one tool, in this case a cutting tool.

It is preferred that the cutting of the base seam and the application of a force which opens and permanently deforms the outer container are carried out in separate, consecutive working steps. The size of the container to be manufactured may be a determining factor in the choice of one or the other variant.

It is recommended that a method of cutting the base seam and exerting a force that opens and permanently deforms the outer container be performed in a plastic blow molding machine, especially when the container is still placed in a closed blow mold. The vessel, which has a temperature of 40 to 70 ° C during the cutting process, is stabilized in this way. The basic advantage is the minimization of processing machines and equipment and the elimination of further work steps. This will reduce costs and increase productivity.

However, in individual cases, it may in turn be advantageous if the cutting of the base seam and the application of a force which opens and permanently deforms the outer container are carried out on a machine which is connected to a plastic blow molding machine. This is also within the scope of the invention.

In most cases, it is a method in which the container is configured in the form of a bottle and the inner bag, in addition to being attached in the base region, is attached in the region of the bottle neck. Particularly preferred herein are methods in which the inner bag is at least partially attached to the wall of the outer container to form the neck of the bottle. This can be easily accomplished during the process. If the diameter of the preform in the region of the future bottle neck is greater than the corresponding diameter of the blow mold, the excess material is squeezed out when the blow mold is closed and a weld seam is formed on the inner bag, or the inner bag is attached to the outer container.

The method can be arranged using a corresponding blow mold so that the neck of the bottle will be formed with a protrusion projecting outward in a radial direction on its face. This may be necessary if the vessel is to be equipped in the next process with a pump or sprayer which is preferably attached to the bottle neck.

In this case, the inner bag may be connected to the outer container by means of a portion of the vertical or horizontal fold, thereby obtaining additional fixation.

Preference is given to process variants in which the projection is formed solely of the material of the outer container.

Accordingly, the at least one pressure relief opening is formed in the base region of the container of the present invention, resulting in cutting, splitting and deformation of the base seam, one side of the base seam of the inner bag remaining adhered to the container and ends of the base seam and thus axially fixed .

Preferred embodiments of the container determine that the container has the shape of a bottle and that the neck of the bottle has a protrusion extending outward in a radial direction on its front side, which may be necessary to accommodate the pump or sprayer. However, the additional fixation in the region of the bottle neck and its embodiment according to claims 21 and 23 are part of the present invention. Such as the feature that the projection is formed solely of the material of the outer container.

The invention is explained in more detail below with reference to various figures in the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a section in the direction of the central axis of the container, a first embodiment of the container; FIG. 2 shows a sectional view in the direction of the central axis of the container through the bottle neck of the second exemplary embodiment of the container; FIG. 3 shows a section in the direction of the central axis of the container by the base region before the cutting process step; FIG. 4 shows a section in the direction of the central axis of the container by the base region after the cutting process step; FIG. 5 is a front elevation of the container base in the direction of the central axis of the container; FIG. 6 is an elevational view of the container base in the direction of the central axis of the container after the steps of the split and deformation process; 7 shows a section in the direction of the central axis of the container by the base region after the steps of the splitting and deformation process. (detail X from Fig. 1)

DETAILED DESCRIPTION OF THE INVENTION

In the following, the same reference numerals refer to like items.

Fig. 1 shows a sectional view of an embodiment of the container 1 in the direction of the central axis 9 of the container. The container, which comprises the outer container 2 and the inner bag 3, is in the form of a bottle in this embodiment. It has a protrusion 7 on its bottle neck 6, which is located at the end of the bottle neck 6, where the container opening 8 is located. The base seam 5 is disposed in the extension of the central axis 9 of the container in the base region 4 of the container 1 around the pressure equalization opening 10 associated therewith. It is clearly shown that the protrusion 7 is made of the material of the outer container 2.

Fig. 2 shows a cross section in the direction of the central axis 9 of the container through the bottle neck 6 of the second embodiment of the container. The neck of the bottle 6 has a rectangular projection 7 on its front side facing the container opening 8. Unlike the embodiment shown in FIG. 1, the rectangular projection 7 has the special feature that it is made of both the material of the outer container 2 and the material of the inner bag 3, so that in addition to its fixing in the base region, the inner bag 3 is particularly fixed in the region of the bottle neck 6.

Fig. 3 shows a cross-section of the base region 4 and the base seam 5 disposed therein, after the blow molding process, but before the cutting process. The base seam 5, which results from the compression of the excess material by the two blow mold halves, has the shape of a dragon's tail after the actual shaping process. The inner bag 3 is clamped between the walls of the outer container 2 in the area of the base seam 5.

Fig. 4 shows a cross-section of the base region 4 and the base seam 5 disposed therein after carrying out a cutting process in which the base seam 5 has been partially cut.

Fig. 5 shows a front view of the base region with a view in the direction of the central axis 9 of the container after partially cutting off the base seam 5. Clearly see the structure of the base seam 5 formed by the central walls of the inner bag 3 and confined on both sides by the walls of the outer container. the forces F that develop in the base region 4 in the direction of the seam to split and open the base seam 5 and deform the outer container 2. The axial force that can optionally be introduced is neither shown nor created in this embodiment.

Fig. 6 shows a front view of the base region 4 with a view in the direction of the central axis 9 of the container and with the base seam 5 located in the base region 4 under the influence of radial forces F acting in the direction of the seam. It is clearly shown how the container deforms and the base seam 5 splits under the influence of these forces, forming a pressure equalization opening 10. In this special embodiment, the inner bag 3 remains fixed on one side of the base seam 5 to the outer container 2 and to the ends 11 of the base seam and is thus axially fixed. The pressure equalization opening 10, which is bounded by the outer container 2 and the inner bag 3, is formed on the opposite side and can thus compensate for the pressure difference between the inner bag 3 and the outer container 2.

Fig. 7 shows a cross-section in the direction of the central axis 9 of the container by the base region 4 and the base seam 5 disposed therein. The pressure relief opening 10 can be clearly seen between the inner bag 3 and the outer container 2.

Claims (24)

A method of manufacturing a container (1) provided with an opening (8) in a container, comprising a substantially rigid outer container (2) and an inner bag (3) disposed thereon, which is in contact with the contents of said container; and a pressure equalization port (10) disposed in the outer container (2) to compensate for the pressure difference between the outer container (2) and the inner bag (3), first producing a preform comprising two coaxial tubes having sufficient length to produce the container, by coextrusion between the open halves of the blow mold, the blow mold is closed and, to form an outwardly projecting base seam (5), excess material in the base region (4) of the container to be produced is forced out in such a way that the material of the outer container (2) which is in contact in the seam area is welded together, the tube which forms the inner bag and the inner bag (3) is subjected to pressure such that the walls of the preform abut on the outlines of the blow mold from the inside, characterized in that when the blow mold is closed and with it by jointly forming the base seam (5), the seam of the inner bag (3) is at least partially fixed in the seam of the outer receptacle and at least one pressure equalization hole (10) is formed by basing the base seam (5) at least partially after radial force and radial force , which acts in the direction of the base seam, develops in the base region in such a way that the base seam (5) is opened by splitting, the pre-pressing temperature being in the range of 40 ° C to 70 ° C when the base seam is cut and 2) is still plastically deformable to a certain extent so that due to this force a permanent deformation occurs which is not neutralized by elastic regeneration. Method according to claim 1, characterized in that when the base seam (5) is at least partially cut off and before the radial force is applied, an axial force is applied which is developed substantially parallel to the longitudinal axis of the container, in such a way that the base seam is at least partially opened by splitting. Method according to claim 2, characterized in that the axial force is introduced in the form of a blow. Method according to any one of the preceding claims, characterized in that the production of the container is carried out without bending a seam in the form of a compressed seam. Method according to any one of the preceding claims, characterized in that when the base seam (5) is at least partially opened by splitting, the material constituting the inner bag (3) remains attached on one side of the base seam (5) to the outer container (5). 2) and at the ends (11) of the base seam while maintaining axial fixation. Method according to any one of the preceding claims, characterized in that the base seam (5) of the outer container (2) is only partially opened by splitting and the seam of the inner bag (3) is fixed by the undigested portion of the base seam of the outer container (2). Method according to any one of the preceding claims, characterized in that the cutting of the base seam (5) and the application of a force which opens and permanently deforms the outer container (2) are carried out simultaneously in one working step. Method according to claims 1 to 6, characterized in that the cutting of the base seam (5) and the application of a force which opens and permanently deforms the outer container (2) are carried out separately in separate working steps. Method according to any one of the preceding claims, characterized in that the cutting of the base seam (5) and the application of a force which opens and permanently deforms the outer container (2) are carried out on a plastic blow molding machine. Method according to claim 9, characterized in that the container (1) is still in a blow mold. Method according to claims 1 to 8, characterized in that the cutting of the base seam (5) and the application of a force which opens and permanently deforms the outer container (2) are carried out on a machine which is connected to a plastic blow molding machine. . Method according to any one of the preceding claims, characterized in that the container (1) is configured in the form of a bottle. Method according to claim 12, characterized in that the inner bag (3) is, in addition to fixing in the base region (4), also fixed in the region of the bottle neck (6). Method according to claim 13, characterized in that the inner bag (3) is attached at least partially in the wall of the outer container (2) during the forming of the bottle neck (6). Method according to any one of claims 12 to 14, characterized in that the bottle neck (6) is configured with a projection (7) on its front side extending outwards in a radial direction. Method according to claim 15, characterized in that the inner bag (3) is connected to the outer container (2) by a vertical or horizontal fold in the region of the projection (7). Method according to claim 15, characterized in that the projection (7) is formed exclusively of the material of the outer container (2). Container (1) with an opening (8) in the container, which substantially comprises a rigid outer container (2) and an inner bag (3) disposed thereon, in contact with said container, preferably manufactured according to any one of claims 1 to 17 characterized in that at least one pressure equalization opening (10) formed from the base seam (5) formed during the pressing process by at least partial cutting, opening at the point of breakage and deforming the base seam () is located in the base region (4) 5) by a radial force in the direction of the seam, the material constituting the inner bag (3) being fixed on one side of the base seam (5) to the outer container (2) and to the ends of the seam after which the inner bag (3) is axially fixed , to form at least one opening (10) for equalizing the constant pressure between the outside of the inner bag (3) and the inside of the outer container (2). Container according to claim 18, characterized in that the container (1) has the shape of a bottle. Container according to claim 19, characterized in that the inner bag (3) is, in addition to fixing in the base region (4), also fixed in the region of the bottle neck (6). Container according to claim 20, characterized in that the inner bag (3) is at least partially attached in the wall of the outer container (2) in the region of the bottle neck (6). Container according to any one of claims 19 to 21, characterized in that the bottle neck (6) is configured with a projection (7) on its front side extending outwards in a radial direction. Container according to claim 22, characterized in that the connection of the inner bag (3) to the outer container (2) is at least partially in the region of the projection (7) and is a vertical or horizontal fold. Container according to claim 22, characterized in that the projection (7) is formed exclusively of the material of the outer container (2).