Patent Publication Number: US-2021163175-A1

Title: Method for producing a liquid guidance device

Description:
This application represents the U.S. national stage of International Patent Application PCT/EP2018/081232, filed on Nov. 14, 2018, which claims priority to German Patent Application No. 10 2017 222 238.7, filed Dec. 8, 2017, the disclosures of which are hereby incorporated by reference in their entirety. 
    
    
     The disclosure relates to a method for producing a liquid-conducting device made of aluminum sheet, in particular as a component of containers or container parts, the liquid-conducting device comprising a functional surface made of anodized aluminum. 
     The production of containers and container parts made of aluminum sheet whose surface is designed as a functional surface made of anodized aluminum has a multitude of uses. Aside from the aluminum oxide layer formed on the surface of the containers promoting effective oxidation protection, such surfaces have proven to be of value in particular as functional or adhesive surfaces which allow a particularly enduring paint coat on the container surface, for example. 
     For instance, DE 10 2013 214 321 A1 discloses a method in which containers produced by forming are immersed in an oxidation bath during an immersion process and the aluminum oxide layer is produced electrolytically on the container surface. In the known method, the entire outer surface of the container is provided with the aluminum oxide layer. 
     EP 2 885 227 B1 discloses a container which has a surface area made of anodized aluminum on a wall in contact with the liquid contained in the container in order to use the porous surface of the aluminum oxide structure for producing gas bubbles and for promoting gas bubble growth when a liquid oversaturated with nitrogen comes into contact with the aluminum oxide surface. The purpose is to use such a functional surface made from aluminum oxide for beverage cans containing beer in order to encourage foaming. 
     For yielding such a functional surface made of aluminum oxide, EP 2 885 227 B  1  proposes providing a plastic container with recesses on its inner side which are provided with anodically produced aluminum oxide. 
     Aside from the fact that filling beverages, such as in particular beer, which are generally consumed cold, in beverage cans made of aluminum sheet being preferred because the temperature conductibility of aluminum sheet is considerably better than that of plastic, consumers generally have reservations against beer filled in plastic beverage cans. 
     The object of the disclosure at hand is therefore to propose a method for producing a liquid-conducting device as well as the liquid-conducting device itself which enables the liquid to come into contact with a functional surface formed on the liquid-conducting device and which can be produced inexpensively. 
     In order to attain this object, the method according to the disclosure has the features of claim  1 . 
     In the method according to the disclosure for producing a liquid-conducting device, which can be realized in particular as a component of containers or container parts, a functional surface made of anodized aluminum is realized on an aluminum sheet by providing a strip- or layer-shaped aluminum sheet with a masking during a masking phase for producing a processing surface defined in its position and structure; by processing the aluminum sheet in an electrolytic process during a processing phase for realizing a functional surface, which is provided with an aluminum oxide layer, on the processing surface; by sizing a body surface of the liquid-conducting device comprising at least one processing surface or functional surface as a component of the aluminum sheet during a sizing phase; and by separating the liquid-conducting device from the strip- or layer-shaped aluminum sheet during a separating phase. 
     In the method according to the disclosure, the position of a functional surface made of anodized aluminum on the surface of the liquid-conducting device is defined by means of a masking, which is applied to the aluminum sheet, as early as in a phase of production in which the material used for the liquid-conducting device, i.e., aluminum sheet, is still available in strips or layers, i.e., as a starting material to be processed, meaning a processing surface is defined as early as in this phase for subsequent subjection of the aluminum sheet to electrolysis, the anodic oxidization subsequently taking place on the processing surface for realizing the functional surface. Consequently the functional surface is realized on the processing surface. 
     Since this means that only the surface areas of the aluminum sheet which are to later form the actual functional surface have to be subjected to electrolysis, only a correspondingly reduced energy input is required for the anodizing process so that significant amounts of energy can be saved in comparison to conventional practice in which the entire surface is anodized. 
     Moreover, the method according to the disclosure enables generating the functional surface at a position exactly defined by the masking of the starting material so that not only effects which can be attained by the functional surface in the liquid, such as foaming the liquid, can be limited locally and in a defined manner but also surface areas which are not supposed to be affected by the functional surface in particular due to an intended aesthetic effect or a desired feel are excluded from anodization. 
     Furthermore, realizing the processing surfaces on a strip or layer level of the aluminum sheet enables a continuous or batch production when transforming the processing surfaces to functional surfaces. 
     If the aluminum sheet is strip-shaped, it is therefore possible to guide the aluminum sheet continuously through an electrolytic bath or to subject it to the electrolyte in a spraying process after the masking has been applied, for example as a varnish coat in a printing process. In a batch operation, the known immersion method can be used for transforming the processing surfaces to functional surfaces, for example. 
     The method according to the disclosure further has a sizing phase in which a body surface of the liquid-conducting device comprising at least one processing surface or functional surface is sized as a component of the aluminum sheet. 
     It is essential for all possible variations of the method that the processing surface, which is transformed to the functional surface by the electrolysis, is defined at a point in time after a previous masking at which the aluminum sheet is still strip- or layer-shaped. 
     Depending on the desired surface quality of the container inner wall, the masking can be realized as a permanent or a temporary masking. 
     The processing phase can be performed before or after the sizing phase, but, as previously indicated, definitely after the masking phase. It is particularly sensible for a processing phase to follow the sizing phase when the sizing phase is to serve not only for determining the outer contour of the processing-surface surroundings, i.e., a body surface of the liquid-conducting device to comprise the functional surface, but also for influencing the surface topography of the subsequently produced functional surface. Such a sizing can be performed using an embossing stamp, i.e., a forming tool. 
     In a preferred embodiment of the method, the sizing phase is performed at the same time as the separating phase so that the liquid-conducting device can be separated from the strip- or layer-shaped starting material in a bending and stamping procedure, for example, and the liquid-conducting device can be shaped in a shared work step. 
     If, according to a preferred embodiment, the separating phase is performed after the sizing phase, the body surface sized during the sizing phase, in particular by forming, can present merely a component or a partial area of the liquid-conducting device produced by being separated from the aluminum sheet. 
     If the separating phase is performed after the sizing phase, which is performed subsequently to the masking phase by forming a formed area, for example, and before the processing phase for forming the functional surface, the electrolysis for transforming the processing surfaces to the functional surfaces can also be performed on the container or the container part instead of on the strip or layer level. 
     The liquid-conducting device according to the disclosure has the features of claim  7 . 
     According to the disclosure, the liquid-conducting device made of aluminum sheet has a functional surface made of anodized aluminum, the functional surface forming merely a partial surface of a body surface of the liquid-conducting device. 
     In a particularly simple embodiment, liquid-conducting devices according to the disclosure can be realized as stirring rods or a body around which the liquid must flow, the stirring rods or body having a functional surface on a carrier surface made of aluminum sheet, the functional surface inducing effects in the liquid caused by the surface of the functional surface upon contact with an oncoming liquid. 
     It is to be noted in general that the effect intended to be caused in the medium hitting the functional surface by the liquid-conducting device provided with the functional surface is not limited to a liquid contact medium as such. In fact, the functional surface can also induce effects in a powder or a different pourable dump material which comes into contact with the functional surface so that the term “liquid-conducting device” does not semantically restrict the patent application at hand to the use with only liquids but can also be interpreted as a “powder-conducting device” or even a “dump-material-conducting device”. 
     The functional surface can be realized asymmetric in particular for inducing special effects in a liquid coming into contact with the functional surface. For instance, when the functional surface is helical in shape, a vortex formation encouraged by the helical shape of the functional surface can enhance bubble nucleation in a beverage oversaturated with nitrogen, the bubble nucleation being induced or supported by the anodized aluminum surface. 
     Preferably the liquid-conducting device is produced by forming a sheet blank. 
     In a preferred embodiment, the liquid-conducting device is realized as a container part. 
     In another embodiment, the liquid-conducting device is realized as a component of a container part. 
     It is particularly preferable if the liquid-conducting device is realized as a container closing device disposed on a container lid. 
     In a particularly preferred embodiment, the liquid-conducting device is realized as a container, the functional surface being able to be realized on only an inner cup edge, for example. 
    
    
     
       In the following, one possibility of performing the method and of a container produced using this method are described in more detail by means of the drawing. 
         FIG. 1  is an isometric view of a beverage container; 
         FIG. 2  shows a container part realized as a container lid of the container shown in  FIG. 1 ; 
         FIG. 3  is a schematic view of the method sequence for producing a container part of the container lid shown in  FIG. 2 ; 
         FIG. 4  is an individual view from the bottom of a container part produced using the method shown in  FIG. 3 ; 
         FIG. 5  is an isometric view of the container part shown in  FIG. 4 . 
     
    
    
       FIG. 1  shows a container  10  which is realized as a beverage can and comprises the following essential parts: a container pot  12  defining a container interior  11  and a container lid  13  sealing container pot  12 . 
     Container lid  13  is shown in an open position in  FIG. 2  and comprises a container closing device  14  provided with an opening tab  15  and a pouring protrusion  16  which forms a liquid-conducting device. Opening tab  15  comprises a pivoting axis  17  which is located in a pivot holder  19  formed in a lid bottom  18 . On one side of pivot axis  17  is located an actuation end  20  which can be pivoted about pivot axis  17  by means of an opening movement  21  so that a push opener  22  of opening tab  15 , which is formed opposite actuation end  20  on the other side of pivot axis  17 , is pivoted against a closing piece (not illustrated) formed in lid bottom  18  and the closing piece is detached from a connection to surrounding lid bottom  18  by means of push opener  22  by destroying a predetermined breaking device  24  and is pivoted downward when continuing opening movement  21  so that a pouring protrusion  25  is formed in lid bottom  18 . 
     As shown in  FIG. 2 , a functional surface  27 , which has an anodically produced aluminum oxide layer on container closing device  14  formed from the aluminum sheet, is located on an underside  26  of the liquid-conducting device realized as pouring protrusion  16  in this instance. Functional surface  27  causes a pouring procedure to induce or enhance foaming when a beverage contained in container interior  11 , e.g., beer, comes into contact with functional surface  27 . 
       FIG. 3  shows the production method for producing container closing device  14  shown in  FIGS. 4 and 5 . 
     As  FIG. 3  shows, production of container closing device  14  starts with a strip-shaped aluminum sheet  32  in this instance, which consecutively passes through several processing stations, namely a masking station  28 , an electrolysis station  29 , a forming station  30  and a separation station  31 . Depending on the configuration of the processing stations, the infeed of strip-shaped aluminum sheet  32  can take place in a continuous or clocked manner. 
     With this shown exemplary embodiment, a masking  34  is applied to the surface of aluminum sheet  32  with a masking lacquer at masking station  28 , the masking lacquer being able to be applied in such a manner using a printing mechanism, for example, that a plurality of processing surfaces  33  are defined preferably in a matrix array on the surface of aluminum sheet  32  with regard to their size, their position and in particular their structure. 
     The exemplary illustration of  FIG. 3  notwithstanding, processing surfaces  33  therefore do not have to be designed as a contiguous surface but can rather be provided with a masking grid formed by the masking lacquer. 
     In a processing phase following the previously described masking phase, aluminum sheet  32  passes through electrolysis station  29  at which an electrolyte is applied to the surface of aluminum sheet  32  by spraying, for example; due to masking  34 , a surface reaction for forming an anodized aluminum oxide surface as a functional surface  27  takes place only in the area of processing surfaces  33  not covered by masking  34 . 
     Subsequently, aluminum sheet  32  passes through forming station  30  for performing a sizing phase during which body surfaces  37 , which are realized as bowl-shaped recesses in the present instance, are sized by realizing formed areas  36  which are produced using an embossing or deep-drawing procedure. 
     Subsequently, liquid-conducting devices  14 , which comprise body surfaces  37  and are realized as container closing devices as shown in  FIGS. 4 and 5  in this instance, are separated in the shown method variation at a separation station  31  during a separating phase of the method. 
     A synopsis of  FIGS. 4 and 5  clearly shows that on the container closing device  14  separated from aluminum sheet  32 , functional surface  27  is realized on a bottom  38  of body surfaces  37  designed as bowl-shaped recesses, bottom  38  forming underside  26  ( FIG. 2 ) of pouring protrusion  16 . Opening tab  15  of container closing device  14  shown in  FIGS. 1 and 2  is formed by a protrusion  39  separated from aluminum sheet  32  in conjunction with formed area  36  during the separating phase. 
     As a synopsis of  FIGS. 4 and 5  clearly shows, a ridge  40  framing functional surface  27  is formed on underside  26  of container closing device  14 , which is produced according to the production method shown in  FIG. 3 , in the area of the pouring protrusion  16  formed by the bowl-shaped recesses  37 , web  40  abutting against lid bottom  18  of a closed container  10  so that ridge  40  enables realizing a hermetically sealed space when lid bottom  18  is closed, in particular if ridge  40  is provided with an adhesive sealing material (not further illustrated), such as in particular silicone, functional surface  27  being shielded from environmental influences and contact to the liquid in the sealed space until the opening procedure described in the introduction of the description is performed and a beverage contained in container interior  11  and functional surface  27  come into contact with each other during the pouring procedure.