Patent Publication Number: US-11021308-B2

Title: Container comprising a recess in the container wall

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a national phase entry under 35 U.S.C. § 371 of PCT/EP2016/078685 filed on Nov. 24, 2016, which claims priority to Swiss Patent Application No. 01719/15 filed on Nov. 25, 2015, the entirety of each of which is incorporated by this reference. 
     FIELD OF THE INVENTION 
     The invention relates to a container 
     produced from a plastic material comprising a container wall delimiting a container interior and an outlet opening provided on the container wall for emptying a product which can be accommodated in the plastic container. 
     PRIOR ART 
     If containers are filled with hot liquids or other contents and closed immediately after the filling procedure, a partial vacuum results in the container interior after the cooling of the content, whereby the walls of the container can partially collapse. Such containers are aesthetically unattractive and cannot be placed correctly in the shelves in this form. To prevent collapsing of the walls, the containers are equipped with a ventilation valve. This valve can be produced from an air-permeable, porous material. The ventilation valve is typically integrated into the closure cap, because it may be installed most easily therein. Ventilation valves made of porous material can also be used, however, to protect the content of the container from microbes and bacteria. For design or functional reasons, an arrangement of the ventilation valve in the closure of the container is not always the optimum location. The demand therefore exists for enabling greater flexibility in the arrangement of the ventilation valve. 
     A closure cap is known from WO 2010/081081, in which a porous element is integrated, to enable a pressure equalization between the container interior and the surroundings. The closure cap according to WO 2010/081081 has a chamber at the lower side of the cover, which has two openings, a lower opening, through which the porous element is inserted into the chamber, and an upper passage opening, which connects the chamber to the surroundings. In order that the porous element is held in the chamber, it can be dimensioned such that a press fit is implemented. Alternatively, the lower edge of the chamber can be folded or provided with an undercut. 
     EP-A-1 068 902 discloses a closure arrangement consisting of an elastic plug for closing a container opening and a filter medium, which is integrated into the plug. The plug has an axial opening, which enables a connection between the container interior and the surroundings. A filter disk, which presses against the cylindrical wall of the passage to form a seal, is arranged in the opening of the plug. It is proposed that the filter disk in the opening be formed integrally with the plug in the injection molding method. However, EP-A-1 068 902 does not provide any instructions as to how this could be implemented. 
     Advantage of the Invention 
     An advantage of the present invention is to disclose a holding device for functional elements on a container, which can also be provided at points other than the container closure. 
     SUMMARY OF THE INVENTION 
     The invention relates to a plastic container comprising a container wall and an outlet opening. 
     The invention provides a container that is formed by extrusion blowmolding and has a recess protruding into the container interior formed on the container wall for accommodating a functional element, wherein the recess is accessible through an insertion opening. The recess can be formed at any point of the container wall and is shaped such that the functional element is securely held in the recess after insertion through the insertion opening. If the container wall is broken through to ensure a contact of the inserted functional element with a product stored in the container interior, the functional element can be held using the container wall sealed in such a manner that a product stored in the container interior cannot reach the surroundings between container wall and functional element. Because the recess is oriented inward, the container surface remains smooth and is not impaired by protrusions. The design of the container can be made extremely flexibly, because it is not impaired by position specifications of the recess. The method of extrusion blowmolding enables the container to be produced rapidly and with accurate dimensions. 
     In one particular embodiment, the recess has a canopy at least in a subregion, which is formed by a section of the container wall delimiting the insertion opening. The canopy ensures that the functional element is securely held in a formfitting manner in the recess, which is used as a receptacle chamber. The canopy can be formed linearly, convexly, or concavely transversely to a center axis of the recess. The container wall can also be formed in this section as a tooth in a canopy over the recess having sharp or rounded tooth head. The recess can also be covered in more than one subregion. The canopy can be used to fix the functional element in the axial direction. The canopy can be formed such that the functional element is fixed in a removable or nonremovable manner. The removability can be ensured by axial force action or radial force action or by a combination of both force actions. 
     The recess advantageously has a wall and a base. The functional element or the insert can thus be pressed into the recess until it strikes against the base. The wall can be formed pyramidal or cylindrical, for example, and can form a polygon in each case viewed in the direction of a longitudinal extension direction of the recess. The wall can also be formed oval, elliptical, or circular viewed in the direction of a longitudinal extension direction of the recess. The recess can also be formed comprising a step, which is formed as a support surface or stop surface for the functional element. However, the wall will usually be formed as circular-cylindrical. 
     Because a passage opening is advantageously provided on the base and/or the wall of the recess, the functional element is connected to the container interior. The opening will generally be arranged such that with inserted functional element, no escape of the product takes place past the functional element. A permanent connection between the atmosphere enclosing the container and the container interior is formed in addition to the outlet opening by the passage opening. 
     To simplify the demolding of the container, the recess has a center axis that is essentially perpendicular to the container wall. 
     According to a further exemplary embodiment, however, it is also conceivable that the recess has a center axis which encloses an angle with the container wall which is less than 90° and greater than 0°, less than 88° and greater than 10°, or less than 80° and greater than 15°. The orientation of the recess in relation to the container surface is thus flexibly selectable. This is advantageous if a special container contour is required or the insertion opening is to be as unobtrusive as possible. In one exemplary embodiment, the angle is less than 45° and greater than 30°. The enclosed angle includes both an angle in the vertical direction and also in the horizontal direction. The direction specification can be related in this case to the footprint of the container. Thus, for example, the center axis can stand perpendicular on the container wall in the horizontal direction and the enclosed angle between container wall and center axis of the recess can be, for example, 75° in the vertical direction. The insertion opening advantageously has a first clear width and the recess widens to a second clear width in the direction of the container interior, wherein the second clear width is greater than the first clear width. The recess can thus enclose the functional element and hold it in a formfitting manner. 
     In a further embodiment, the insertion opening has a first clear width and the recess widens in the direction of the container interior in relation to the first clear width to a second clear width and subsequently constricts to a third clear width. This design of the recess is advantageous if the functional element is inserted with its smaller-diameter end in front into the recess. The recess is embodied in this case such that it encloses the lateral surface of the functional element and the undercut holds the larger-diameter end in a formfitting manner. The constriction from the second clear width to the third clear width can take place suddenly, for example, by means of an offset, a step, or a projection. This constriction from the second clear width to the third clear width can also take place continuously or discontinuously over a predetermined distance. The first clear width can be smaller than, equal to, or larger than the third clear width. 
     It has proven to be advantageous if the maximum canopy of the recess measured transversely to a center axis of the recess is between 0.05 mm and 1 mm or between 0.25 mm and 0.5 mm. Due to these dimension features, the canopy has an overlap with respect to the recess which holds the functional element reliably in the recess, on the one hand, and enables the functional element to be pressed through the insertion opening, on the other hand. The maximum canopy is the amount between the edge of the canopy which simultaneously delimits the insertion opening, and the wall of the recess. 
     Because the wall of the recess and a section of the canopy adjoining the wall of the recess advantageously enclose an angle between 20 and 50° or between 30 and 40°, the undercut can be demolded and forms a sufficient friction lock for the connection of functional element and recess. 
     The recess advantageously has an essentially rotationally-symmetrical design. The recess is simpler to demold than if it had a polygonal formation. Fits between functional element and recess are also simpler to perform if they have a rotationally-symmetrical shape. 
     A further aspect of the invention relates to an above-described container having a functional element accommodated in the recess. Due to the combination of recess and functional element, they can be adapted accurately to one another, whereby the fitting surface between functional element and recess wall is generally liquid-tight, but can also be designed as gas-tight in the case of special demands. 
     In another particular embodiment, an outer shape of the functional element and an inner shape of the recess correspond to one another such that the functional element is held fluid-tight in the recess in relation to a product stored in the container interior. The fitting surface between functional element and wall of the recess can be embodied as liquid-tight. The form fit, caused by the canopy, holds the functional element reliably in the recess, even if an overpressure prevails in the container interior. The canopy can prevent the functional element from being displaceable out of the recess in the direction of the center axis of the recess. The functional element is advantageously formed as a collar bushing. The functional element is adapted in its outer contour by the formation of the collar to the contours of the recess and is thus accommodated in a particularly well-holding and well-sealing manner in the recess. The functional element can also have the form of a sleeve or a bushing without collar. 
     A second passage opening is advantageously provided on the functional element, to enable a gas exchange between container interior and the surroundings. Depending on the function of the functional element, it can be directly in contact with the container interior, to equalize pressure or fulfill other tasks described below. The second passage opening can be smaller than 5 μm, to hold back products from the container interior, and can be smaller than 20 μm, to hold back pasty products from the container interior. At both opening sizes, an unobstructed gas exchange is possible between surrounding atmosphere and container interior. The second passage opening is closed by a gas-permeable membrane for the pressure equalization between container interior and surroundings. The membrane is only permeable to gases and is liquid-tight. If an internal pressure which is greater than the ambient pressure builds up in the container interior due to a change of sea level or due to gas formation, this internal pressure can thus be equalized through the membrane. It is also conceivable that a partial vacuum in the container can be equalized. A partial vacuum can arise, for example, if a hot product is poured into the container and is cooled in the closed container. 
     The membrane function can be implemented in simplified form by the functional element advantageously being a sintered, porous part made of HDPE. The functional element is in one piece and is accordingly also easily producible. Gas can be exchanged between container interior and surroundings through the porous part, but liquid cannot pass through the functional part. 
     In a further embodiment, the functional element is a shelf life indicator. The shelf life indicator is connected to the container interior and reacts to parameters which permit a change in the filled product to be concluded. Thus, for example, the formation of a gas or a pressure change can be recognized. 
     A further possibility is that the functional element contains a chemical substance, which can be in fluid connection with the container interior. Thus, for example, the continuous additional metering of a natural antimicrobial substance can lengthen the shelf life of the filled product. The chemical substance can also be an odor absorber, oxygen absorber, water vapor absorber, or a CO 2  absorber. In general, a chemical substance can be placed in the functional element, which captures gases arising during the storage of the container. 
     It is also conceivable that the functional element is an indicator which indicates if the refrigeration chain of the product stored in the container was interrupted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages and features result from the following description of an exemplary embodiment of the invention with reference to the schematic illustrations. In the figures, which are not to scale: 
         FIG. 1 : shows a cross section through the container wall of a plastic container comprising a recess in a first embodiment; 
         FIG. 2 : shows a cross section through the container wall of a plastic container comprising a recess in a second embodiment; 
         FIG. 3 : shows a cross section through the container wall of a plastic container comprising a recess in a third embodiment; 
         FIG. 4 : shows a cross section through the container wall of a plastic container comprising a recess in a fourth embodiment; and 
         FIG. 5 : shows a side view of a plastic container comprising a recess. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A detailed view of a container made of plastic material is shown in  FIGS. 1 to 4 . The container is identified in its entirety with the reference sign  11 . A recess  15  is formed in a container wall  13  of the container  11  at an arbitrary point. The recess  15  is used as a receptacle chamber for a functional element  17 . The functional element  17  is inserted through an insertion opening  19  into the recess  17 . In  FIG. 5 , the recess  15  is provided by way of example in the container wall  13  of the container  11 , which is formed in the present exemplary embodiment as a side wall, in the vicinity of the container bottom. The recess  15  is arranged at a point at which the functional element  17  can be in contact with the product stored in the container  11 , even if the container is partially emptied. Any position on the container wall  13  is possible in principle. 
     The recesses or the receptacle chamber  15 , respectively, has, in addition to the insertion opening  19 , a wall  21  and a base  23 . If the functional element  17  is accommodated in the recess  15 , it is may be configured to touch the base  23 . The functional element  17  can be held in a friction-locked and/or formfitting manner in the recess  15 . The external dimensions of the functional element  17  and the internal dimensions of the recess  15  are adapted to one another for holding under friction lock such that a press fit is provided. Holding under friction lock is shown in  FIG. 4 . 
     For holding the functional element  17  in the recess  15  with a form fit, the recess  15  has a canopy  25 . To form the canopy  25 , the recess  15  has a first clear width  27  in the region of the insertion opening  19 , which widens in the direction of the container interior to a second clear width  29 . The external dimensions of the functional element  17  are essentially adapted to the canopy dimensions. For this purpose, the functional element  17  widens from a collar  31  to a larger-diameter shoulder  33 . 
     The difference between first and second clear width  27 ,  29  is between 0.6 and 1 mm or between 0.7 and 0.9 mm. This difference enables reliable holding of the functional element  17  in the recess  15  and enables the shoulder  33  to still fit through the smaller-diameter insertion opening  19  with widening thereof. 
     The transition between first and second clear width  27 ,  29  is formed by a canopy flank  35 . The flank  35  forms an angle between 20 and 50° or between 30 and 40° with the wall  21  and/or the center axis  37  of the recess. 
     If the center axis  37  is perpendicular to the partition plane of the container  11 , the canopy is thus simpler to demold than with another orientation of the center axis  37 . This is because the half shells of the container open in the direction of the center axis  37 . However, it is also conceivable that the center axis has an angle between 0 and 90°, between 10 and 88°, and or between 15 and 80° and the recess  15  is nonetheless demoldable. Movable elements in the mold are also conceivable to implement the demolding. Recesses  15  having such an orientation are desired if the container design requires it. For example, an orientation of the center axis  37  perpendicular to the container surface is advantageous for a uniform container design. 
     It is also conceivable that according to  FIG. 3 , the recess  15  constricts proceeding from the second clear width  29  to a third clear width  39 . This design of the recess  15  is selected if the functional element  17  is accommodated with the collar  31  in front in the recess  15 . 
     For reasons of simplified production, the functional element  17  and the recess  15  may have a rotationally-symmetrical design. 
     To enable a fluid exchange between container interior and surroundings, a first passage opening  41  can be provided at the base of the recess  15 . It is obvious that for this reason a second passage opening  43  can also be provided at the functional element  17 . As  FIGS. 3 and 4  show, the second passage opening  43  can be set back in accordance with the outer contour of the functional element  17 . 
     The functional element  17  can perform greatly varying tasks. The following applications are conceivable by way of example and therefore not as an exhaustive list: 
     As shown in the figures, the functional element  17  can be a housing having the second passage opening  43  provided therein. A membrane  45  is inserted into the second passage opening  43 . Since the membrane is expediently only permeable to gases, the same pressure always prevails in the container interior as in the surroundings. A gas exchange therefore takes place between container interior and the atmosphere enclosing container  11 . A deformation of the container  11  because of partial vacuum or overpressure in the container interior can therefore be prevented. The membrane  45  can be produced from typical membrane materials, for example, polyethylene (PE) or polytetrafluoroethylene (PTFE), polyamide (PA), or polyacrylonitrile. 
     A simplified membrane function of the functional element  17  can be achieved in that the functional element  17  is a sintered, porous plug, for example, made of HDPE. This porous material has the properties of a gas-permeable membrane. 
     The functional element  17  can also be a shelf life indicator. It is connected for this purpose to the container interior. If a gas should form in the container interior, which permits the end of the shelf life of the field product to be concluded, the functional element can thus change the color. For example, a chemical substance can be present in the functional element, which changes the color by reacting with the gas arising. 
     It is also conceivable that a chemical substance is contained in the functional element  17  which can be emitted through the first and second passage opening  41 ,  43  into the container interior. The shelf life of the stored product can thus be lengthened. 
     A chemical substance can also be placed in the functional element  17 , which indicates an interruption of the refrigeration chain and thus suggests a spoiled food in the container. 
     The container  11  having the above-described recess  15  may be produced in the production method of extrusion blowmolding. The method described in EP 2 227 369 represents one possibility for the production. 
     A displaceable mandrel can be provided in one of the mold half shells for producing the canopy  25 . Upon opening of the half shells, the mandrel is displaced from the mold half shell into the cavity at the same velocity as the separation of the mold half shells takes place, and therefore the mandrel does not move in relation to the container upon opening of the mold half shells. The mandrel is then withdrawn from the molded recess  15 , wherein the container is held back by a counter holder. 
     If the recess  15  is formed as in  FIG. 4 , the mandrel can thus be drawn out of the recess  15  upon opening of the half shells, without a counter holder being necessary for holding back the container.