Patent Publication Number: US-2021179336-A1

Title: Packaging Material with a Fixed Desiccant Container, and Method

Description:
PRIOR ART 
     Systems for processing or analyzing a chemical or biological sample, for example microfluidic or lab-on-a-chip systems, often comprise moisture-sensitive devices or components, for example microfluidic cartridges, in which lyophilized reagents are pre-stored. For storage with long-term stability, these devices or components thereof are therefore stored prior to use, often in sealed or welded composite packaging. 
     DISCLOSURE OF THE INVENTION 
     Advantages of the Invention 
     Against this background, the invention relates to a packaging material for packaging a device, in particular a microfluidic device. The packaging material comprises a desiccant container, in particular a desiccant pouch, wherein the desiccant container is fixed by way of melting the packaging material, in particular a material of the packaging material, at isolated points. 
     A device can be understood in particular to be a component, an apparatus or a part of a system for processing or analyzing a chemical or biological sample, for example for biochemical or medical purposes. A packaging material can be understood in particular to be a packaging or a part of a packaging, in particular a sleeve for the partial or complete encapsulation of the device. A packaging material can also be understood in particular to be a film with one or more layers, in particular a composite film, which can be designed for example in the form of a pouch or a bag. A desiccant container can be understood in particular to be a container for receiving a desiccant. The desiccant container can have a stiff or deformable sleeve. The desiccant container is preferably a desiccant pouch, that is to say a pouch for receiving desiccant. The desiccant container preferably already contains the desiccant prior to being fixed to the packaging material. A desiccant is to be understood in particular as a substance or a substance mixture which can extract water or other liquids, for example solvents, from a proximate object for the purpose of drying or keeping dry. Typical desiccants are for example silica gel, zeolites, sodium sulfate, magnesium sulfate, aluminum oxide, calcium, calcium hydride, calcium oxide, calcium sulfate, potassium carbonate, potassium hydroxide, copper sulfate, lithium aluminum hydride, or sodium hydroxide. Melting of the packaging material is to be understood in particular to be the softening and/or deformation of the packaging material, in particular under the effect of heat, in particular followed by resolidification through cooling. In the process, a material of the packaging material and/or a material of the desiccant container can be melted at isolated points for the fixing of the desiccant container, in particular a material of a sleeve of the packaging material or of the desiccant container, respectively. Fixing of the desiccant container to the material by way of melting at isolated points is to be understood in particular as meaning that a fixed connection is produced between the material and the desiccant container by way of a partial softening of the material, in particular brought about by heat, followed by contact connection of the softened material with the desiccant container, followed by a renewed hardening, in particular by cooling, of the material. Expressed differently, the material is fused to the desiccant container by way of softening of the material. As an alternative or in addition, a partial softening of the material of the desiccant container, in particular brought about by heat, may also take place for fusing to the packaging material. 
     The packaging material according to the invention has the advantage that, by virtue of being fused to the packaging material at a well-defined location, the desiccant container is fixedly arranged with respect to the packaging material and with respect to the device to be packaged by means of the packaging material. Consequently, the desiccant container can advantageously be immovably and stably positioned close to desired, in particular moisture-sensitive, locations of the device to be packaged. In addition, slipping of the desiccant container in the case of movement of the packaged device advantageously does not take place, with the result that the risk of damage to sensitive regions of the device by the desiccant container, for example in the form of scratch marks, is reduced. It is also of particular advantage that a material of the packaging material acts as connecting means between the packaging material and the desiccant container. An additional substance, in particular an adhesive, is consequently not necessary for the connection, thereby ruling out a possible detrimental effect of the substance on the device. In particular, an outgassing, which is otherwise usual in the case of many adhesives, or an unintended transfer of adhesive residues to the device is avoided. It is furthermore of advantage that, when the packaging is being opened, the desiccant container generally remains fixed and is not unintentionally separated from the packaging. This leads to a high degree of user friendliness of the packaging material according to the invention. 
     The desiccant container is preferably fixed via penetration of a material of the packaging material at isolated points into a sleeve of the desiccant container. This advantageously produces a particularly reliable connection of the desiccant container to the packaging material. The sleeve of the desiccant container is configured here such that the molten material of the packaging material can penetrate at least partially into the sleeve. In particular, the sleeve can comprise fibers or a fibrous material so that the penetration leads to the material, for example paper, cotton wool or another fibrous material, for example in combination with plastic, at least partially enclosing a plurality of fibers. A form fit created in this way between the material and the sleeve of the desiccant container is advantageously particularly stable. 
     The invention also relates to a method for connecting the desiccant container to the packaging material, i.e. a method according to the invention for producing the packaging material according to the invention. The desiccant container can thus be in particular a desiccant pouch, as stated above, and the device can be in particular a microfluidic device. In a first step of the method, the packaging material and the desiccant container are positioned relative to one another. In a second step, at least one region of the packaging material is heated, with the result that the packaging material melts at isolated points in the region for the connection of the desiccant container to the packaging material. As described above, part of the material preferably penetrates into the sleeve of the desiccant container here, preferably for partially enclosing fibers of the sleeve. While the material cools, the connection of the desiccant container to the packaging material preferably hardens. 
     In one particularly advantageous configuration of the invention, the packaging material comprises composite material, in particular an aluminum/polypropylene composite. This has the advantage, on the one hand, that composite materials constitute packaging materials which are well-suited according to the invention, and, on the other hand, melt easily under the effect of heat. In this case, the meltable material preferably comprises plastic. 
     In one advantageous configuration of the invention, the region is heated until at least a part of the sleeve of the desiccant container likewise softens or melts. This has the advantage that the part of the sleeve and the molten material can mix with one another for a particularly strong connection. The sleeve of the desiccant container preferably has a meltable material, in particular plastic, for this purpose. 
     According to one particularly advantageous refinement of the invention, the desiccant container is arranged at a predefined location with respect to the device prior to the heating. This has the advantage that it can be easily ensured that the desiccant container is located close or directly adjacent to a desired, in particular moisture-sensitive, location of the device after the device has been packaged. Sealing of the packaging material for the purpose of closing the device can take place here prior to, during or after the heating. 
     In one particularly preferred refinement of the invention, a force is exerted on the packaging material in the direction of the desiccant container during or after the heating. This advantageously assists a connection of the packaging material to the desiccant container. 
     The region is heated preferably by way of a contact connection with a heating die. This has the advantage that the required heat is introduced in a well-defined and delimited manner, and thus heat-sensitive parts of the packaging material or of the device can easily remain unaffected. 
     In one advantageous refinement of the invention, the packaging material has an embossed contour on a side of the melting that faces away from the desiccant container. The contour can preferably code an item of information which is useful for a user of the device. In one particularly advantageous configuration of the method according to the invention, the contour is embossed by way of the heating die. The heating die comprises the required embossed structure for this purpose. This has the advantage that both the desiccant container can be connected to the packaging material and the contour can be created in only one step. 
     According to one preferred refinement of the invention, an opening of the packaging material is sealed, after the device is introduced into the packaging material, jointly with the heating of the region. In this refinement, the packaging material preferably has the form of a pouch for receiving the device. In particular when the sealing takes place likewise by way of partial melting of the material of the composite pouch, this refinement has the advantage that two method steps can be carried out in one. 
     By way of example, in this respect the heating die comprises a second region for heat-sealing the opening of the packaging material. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the invention are schematically illustrated in the drawings and explained in more detail in the description hereinbelow. The same reference signs are used for the similarly acting elements illustrated in the various figures, a repeated description of the elements being dispensed with. 
       In the drawings: 
         FIG. 1  shows an exemplary embodiment of the packaging material according to the invention, and 
         FIG. 2  shows a flow chart of an exemplary embodiment of the method according to the invention. 
     
    
    
     EMBODIMENTS OF THE INVENTION 
       FIG. 1  schematically shows one exemplary embodiment of the packaging material  100  according to the invention for packaging a device  200 . In this example, the device  200  is a microfluidic device, specifically a cartridge  200  for a lab-on-a-chip system. The packaging material  100  comprises a desiccant container  50 , in this example a desiccant pouch  50  filled with desiccant  51 , for example silica gel. The desiccant container  50  is fixedly connected to the packaging material  100  by way of melting  110  of a material  120  of the packaging material  100  at isolated points. 
     In this example, the packaging material  100  is a pouch  100  of composite material, for example a pouch produced from a composite film with the layer sequence of polyethylene, aluminum, polypropylene. Illustrated in  FIG. 1  is that the cartridge  200  is already located in the composite pouch  100  and the opening  101  of the composite pouch  100  is already sealed. The desiccant pouch  50  is also already connected to the pouch  100  by way of the melting  110 . In this example, the desiccant pouch  50  comprises a fibrous material, so that it was possible for the molten material  120  to penetrate partially into the sleeve  52  of the desiccant pouch  50  and enclose fibers of the sleeve  52  for a form-fitting connection of the desiccant pouch  50  to the composite pouch  100 . By way of example, the desiccant pouch  50  comprises a fibrous substance, cotton wool, a nonwoven material or paper for this purpose. As an alternative or in addition, the sleeve  52  can comprise a meltable material  53  for fusing to the material  120  of the composite pouch  100 . As is also schematically illustrated in  FIG. 1 , the heat required for the melting has been introduced by way of a heating die  300  having an embossed structure  310 , and at the same time a contour  130  has been embossed onto the outer side of the composite pouch  100 . The contour  130  can code information about the cartridge  200  that is useful for a user of the device  100  and can do so in the form of text or symbols, for example an indication relating to the origin, type and/or usability of the cartridge  200 . 
       FIG. 2  schematically shows a flow chart of an exemplary embodiment of the method  500  according to the invention, by means of which for example the packaging, illustrated in  FIG. 1 , of the cartridge  200  can be achieved by the packaging material  100  and connected desiccant container  50 . In a first step  501  of the method  500 , the desiccant pouch  100  is placed onto a predefined location  210  of the cartridge  200 , for example close to the particularly moisture-sensitive front portion  210  of the cartridge. In a second step  502 , the cartridge  200  and the desiccant pouch  100  are provided in the composite pouch  100 . The first step  501  and the second step  502  can also take place in parallel or in a reverse order. In a third step  503 , the opening  101  of the composite pouch  100  is sealed. In a fourth step, the material  110  of the composite pouch  100  that adjoins the desiccant pouch  50  is heated, with the result that the material  110  melts and thus penetrates partially into the sleeve  52  of the desiccant pouch  50  for a form fit with the fibers of the sleeve  52 . In this case, the heating takes place by way of a contact connection of the embossed structure  310  of the heating die  300  with the material, with the result that also at the same time the contour  130  is embossed into the composite pouch  100 . If a contour  130  is not required, a heating die with a flat die surface can also be used. By way of example, the die is heated to a temperature between 190 and 250 degrees Celsius and for a heat effect duration on the material  110  of 1 to 5 seconds. The duration depends here on the thickness and the material composition of the composite material, such that the material  110  is softened up to that side of the composite pouch  100  which makes contact with the desiccant pouch  50 . In this case, the heating die  300  can exert for example a contact pressure of between 1 and 15 newtons. The third step  503  of sealing the composite pouch  100  and the fourth step  504  of heating and embossing can preferably also be carried out at the same time here, in particular when the sealing likewise takes place by way of a partial melting of the material of the composite pouch  100 . In a fifth step  505 , the composite pouch  100  can be conveyed further after cooling.