Abstract:
A mixing and dispensing device ( 1 ) for preparing and applying an adhesive consisting of at least two components, comprises a syringe body ( 2 ) which encloses a substantially cylindrical cavity ( 3 ), wherein the cavity ( 3 ) is divided into at least two chambers separated from each other by a movable separating element ( 6 ), wherein—a first chamber ( 4 ) has a first component ( 13 ) of the adhesive and—a second chamber ( 5 ) has a second component ( 14 ) of the adhesive, wherein a flow path ( 11 ) between the first chamber ( 4 ) and the second chamber ( 5 ) can be released by moving the separating element ( 6 ).

Description:
[0001]    The present invention relates to a mixing and dispensing device for preparing and applying an adhesive consisting of at least two components. The present invention further relates to a method for preparing and applying an adhesive consisting of at least two components. 
         [0002]    An adhesive is understood here and in the following to mean a mainly organic process material which is used for adhesively bonding elements and/or for sealing. 
         [0003]    Preparing adhesives comprising a plurality of components in a cartridge system is known, for example from EP 2 497 721 A1. In this case, each component is stored in a cartridge and prepared individually. The components are first mixed during application, in a mixing device that is placed on the cartridge system. A system of this kind has the advantage that the components that are separate from one another can be stored for a very long time. However, cartridge systems are relatively expensive. In addition, each application leads to a loss of material owing to residue remaining in the mixing device, and this is associated with very high material costs and even with financial losses in certain applications, for example in the field of dentistry. 
         [0004]    In contrast, single-component adhesives are easy to use but often cannot be stored for very long. 
         [0005]    One problem of the present invention is that of providing a mixing and dispensing device for preparing and applying an adhesive that consists of at least two components (“two component adhesive”), is user-friendly and at the same time has a very good storage life. 
         [0006]    This problem is solved by the subject matter of the independent claims. Further embodiments are the subjects of the dependent claims. 
         [0007]    According to one aspect of the invention, a mixing and dispensing device is provided for preparing and applying an adhesive that consists of at least two components and comprises a syringe body that encloses a substantially cylindrical cavity. The cavity is divided into at least two chambers that are separated from one another by a movable separating element, a first chamber comprising a first component of the adhesive and a second chamber comprising a second component of the adhesive. A flow path can be released between the first chamber and the second chamber by moving the separating element. 
         [0008]    The mixing and dispensing device thus comprises at least two chambers, but can also comprise more than two chambers, for example if more than two components are intended to be provided separately from one another. Said device has the advantage of a very good storage life since the at least two components are kept separate from one another. The adhesive is only prepared immediately before use by mixing the components and is then readily available in the mixing and dispensing device and can be used as a single-component adhesive. The mixing and dispensing device is thus also very user-friendly. 
         [0009]    The mixing and dispensing device can be particularly advantageously used if the individual components are liquid and have a low viscosity. However, it is also conceivable to use said device for other systems. For example, a component may also be present in powder form or at least one liquid component may have a high viscosity. 
         [0010]    It has become apparent that adhesives prepared in the mixing and dispensing device can still be used 24 hours after they have been prepared. The pot life of the adhesive is thus significantly increased in comparison with the known multi-component systems. 
         [0011]    In one embodiment, the flow path is formed between the separating element and an inner wall of the syringe body. For this purpose, the flow path can be formed for example in an outward bulge of the syringe body. In this embodiment, the wall thickness of the syringe body can be the same in all regions. In an alternative embodiment, the flow path is formed in a channel inside a wall of the syringe body. In this embodiment, the wall thickness of the syringe body is accordingly reduced in one region such that a flow path is formed in said region. 
         [0012]    In one embodiment, the mixing and dispensing device further comprises a piston for moving the separating element in the longitudinal direction of the syringe body and for dispensing adhesive. Syringes comprising pistons of this kind are known in particular from the field of medicine. The piston is pushed into the syringe body in order to move the separating element such that the flow path is released. Pushing the piston again forces the component located in the chamber closest to the piston into the other chamber, therefore allowing the components to be completely mixed. Pushing the piston yet again causes ready-mixed adhesive to be dispensed. Operating the piston is highly intuitive, and therefore the mixing and dispensing device is easy to use. 
         [0013]    In one embodiment, the first component is formed as a liquid having a first color and the second component is formed as a liquid having a second color. This has the advantage that the mixing of the components can be visually monitored by the user when using a typical transparent syringe body. It can also be determined whether residues of a component are left in a chamber. 
         [0014]    In one embodiment, the mixing and dispensing device comprises a dispensing opening at one end of the syringe body, a mixing device being arranged in the region of the dispensing opening. The mixing device, which can be formed for example as a static mixer, can improve the intermixing process, in particular for systems in which at least one component has a relatively high viscosity. 
         [0015]    In one embodiment, the mixing and dispensing device comprises a dispensing opening at one end of the syringe body, which opening can be closed by a stopper. This has the advantage that a sealed closure of the mixing and dispensing device is possible, and therefore the pot life of the ready-to-use mixture is increased. 
         [0016]    The adhesive can be in particular an anaerobically curing adhesive or a methyl methacrylate adhesive. 
         [0017]    According to another aspect of the invention, a method is provided for preparing an adhesive consisting of at least two components, the method comprising the following:
       providing the described mixing and dispensing device;   moving the separating element and releasing a flow path between the first chamber and the second chamber;   mixing the first component of the adhesive with the second component of the adhesive.       
 
         [0021]    The mixing process can be carried out in particular passively by waiting or actively by shaking and/or pressing one component into the other chamber. 
         [0022]    The method has the advantage that it is very simple to carry out, in particular by pushing a piston into the syringe body. Said method can be carried out immediately before using the adhesive, although the adhesive can still be used 24 hours after the method has been carried out depending on the chemical system used. 
         [0023]    Embodiments of the invention are described in more detail in the following with reference to drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a schematic view of a mixing and dispensing device for an adhesive according to a first embodiment of the invention in a first position of use; 
           [0025]      FIG. 2  is a schematic view of the mixing and dispensing device according to  FIG. 1  in a second position of use; 
           [0026]      FIG. 3  is a schematic view of the mixing and dispensing device according to  FIG. 1  in a third position of use; 
           [0027]      FIG. 4  is a schematic perspective view of the syringe body of the mixing and dispensing device according to  FIG. 1 ; 
           [0028]      FIG. 5  is another schematic perspective view of the syringe body of the mixing and dispensing device according to  FIG. 1 ; 
           [0029]      FIG. 6  is a schematic view of the syringe body of the mixing and dispensing device according to  FIG. 1  in a longitudinal cross section; 
           [0030]      FIG. 7  is a schematic view of a detail from  FIG. 6 ; and 
           [0031]      FIG. 8  is a schematic view of a detail of a mixing and dispensing device according to a second embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]      FIG. 1  shows a mixing and dispensing device  1  for an adhesive that, in the example shown, consists of two components. The mixing and dispensing device  1  comprises a syringe body  2  comprising a wall  12  that encloses a substantially cylindrical cavity  3 . The cavity  3  is divided into a first chamber  4  and a second chamber  5  by means of a separating element  6  that can be moved longitudinally inside the syringe body  2 . 
         [0033]    The first chamber  4  is filled with a first component  13  of the adhesive and the second chamber  5  is filled with a second component  14  of the adhesive. In the first position of use of the mixing and dispensing device  1  shown in  FIG. 1 , the separating element  6  rests tightly against the inside of the wall  12 , meaning that it is not possible to exchange gas or liquid between the first chamber  4  and the second chamber  5 . 
         [0034]    The mixing and dispensing device  1  further comprises a piston  7  which can be pushed into the syringe body  2 . In the first position of use shown in  FIG. 1 , most of the piston  7  protrudes out of the cavity  3  and only the front end  8  thereof is pushed into the cavity  3 . The front end  8  of the piston  7  and the separating element  6  define the second chamber  5 . The first chamber  4  is delimited by the separating element  6  and the front end  18  of the syringe body  2 . 
         [0035]    A channel  10  is arranged in the wall  12  of the syringe body  2  at a point in a central region. The channel  10  is formed by a reduction in the wall thickness. A flow path can be formed by the channel  10  when the separating element  6  is pushed to the level of the channel  10 . This is shown in  FIG. 2 . 
         [0036]    The mixing and dispensing device  1  further comprises a dispensing opening  9  at the front end  18  thereof, by means of which opening ready-mixed adhesive can be dispensed by applying pressure to the piston  7 . A stopper (not shown) can be placed on the dispensing opening  9  in the form of a tip as required in order to close the cavity  3  in an airtight manner. Ready-prepared adhesive can then be stored for 24 hours, for example. 
         [0037]    The mixing and dispensing device  1  can be stored in the first position of use. Long-term storage is possible owing to the separation of the components  13 ,  14 . 
         [0038]      FIG. 2  shows the mixing and dispensing device  1  in a second position of use. This is achieved by the piston  7  being pushed some way into the cavity  3 . The second component  14  located in the second chamber  5  or possibly also gas located in the second chamber  5  is first compressed by means of the pressure on the piston  7 . As a result, the pressure in the second chamber increases and applies a force on the separating element  6 . If said force is sufficiently large, the separating element  6  is also pushed in the longitudinal direction of the syringe body  2  and reaches the level of the channel  10 . The separating element  6  now no longer fills the entire cross section of the cavity  3 . As a result, a flow path  11  is formed by the channel  10 , by means of which flow path the second component  14  flows into the first chamber  4 . Here, said second component is mixed with the first component  5  and reacts therewith to form the ready-prepared adhesive  15 . 
         [0039]    By applying pressure to the piston  7 , said piston is guided as far as the separating element  6  such that the total content of the second chamber  5  enters the first chamber  4 . 
         [0040]    Mixing the components  13 ,  14  can be assisted by waiting or shaking. 
         [0041]    The second position of use is accordingly used for the preparation of the adhesive from the components  13 ,  14 . 
         [0042]      FIG. 3  shows the mixing and dispensing device  1  in a third position of use, which is used for dispensing the prepared adhesive  15 . If the preparation of the adhesive  15  is complete, said adhesive can be pressed out of the syringe body  2  through the dispensing opening  9  by means of further pressure on the piston  7 . In the process, the piston  7  pushes the separating element  6  along. 
         [0043]      FIGS. 4 and 5  are two perspective views of the syringe body  2  itself. In this view, a rim  16  is arranged around the dispensing opening  9 , on which rim a stopper for closing the mixing and dispensing device  1  can be placed. 
         [0044]      FIG. 6  is a longitudinal cross section of the syringe body  2 . In this case, it can be seen that the longitudinal cross section of the channel  10  is triangular in this embodiment. However, said channel can also be rectangular or semi-oval, for example. Said channel is shown in detail in  FIG. 7 . In this case, it can be seen that the channel  10  is formed by a locally reduced wall thickness of the wall  12 . 
         [0045]      FIG. 8  shows an alternative embodiment of the flow path. In this case, the wall  12  has an outward bulge  17  and the wall thickness can be uniform in this embodiment. 
         [0046]    In principle, the mixing and dispensing device  1  is suitable for different types of adhesive systems that are mixed from at least two components. 
       EXAMPLES 
     Example 1 
       [0047]    The mixing and dispensing device  1  can be used for a methyl methacrylate adhesive, for example. One example is an adhesive having the following composition: 
         [0048]    Chamber  1 : monomer (triEGMA)+initiator (peroxide), 2%+yellow pigment Chamber  2 : monomer (HEMA)+sPP (syndiotactic polypropylene) accelerator Cu (BF4)2, 1% in a ratio of 2:1. 
         [0049]    The mixing and dispensing device comprising said adhesive system demonstrates good stability during storage. If the content of the second chamber is pressed into the first chamber, the mixture turns green. The degree of mixing can be checked by means of the color. The mixture starts to anaerobically cure after approximately 25 minutes, although the supernatant liquid can still be used after 24 hours when the mixing and dispensing device is stored upright on the stopper. 
         [0050]    It would also be conceivable for this system to provide the total monomer together with the accelerator in one chamber, while the second chamber only contains the initiator. 
       Example 2 
       [0051]    The following composition is an example of an anaerobically curing adhesive: 
         [0052]    Chamber  1 : monomer (triEGMA)+initiator (peroxide), 1%+reducing agent, 1% 
         [0053]    Chamber  2 : monomer (HEMA)+sPP (syndiotactic polypropylene) accelerator MX2, 0.5% 
         [0000]    in a ratio of 2:1. 
         [0054]    The mixing and dispensing device comprising this adhesive system demonstrates good stability during storage. The mixture starts to anaerobically cure after approximately 25 minutes, although the supernatant liquid can still be used after 24 hours when the mixing and dispensing device is stored upright on the stopper. 
       LIST OF REFERENCE SIGNS 
       [0055]      1  mixing and dispensing device 
         [0056]      2 ,  2 ′ syringe body 
         [0057]      3  cavity 
         [0058]      4  first chamber 
         [0059]      5  second chamber 
         [0060]      6  separating element 
         [0061]      7  piston 
         [0062]      8  front end 
         [0063]      9  dispensing opening 
         [0064]      10  channel 
         [0065]      11  flow path 
         [0066]      12  wall 
         [0067]      13  first component 
         [0068]      14  second component 
         [0069]      15  adhesive 
         [0070]      16  rim 
         [0071]      17  bulge 
         [0072]      18  front end