Abstract:
A container for receiving moisture sensitive goods includes a container body (15) and a cap (26) shaped to establish a leak-proof seal between the container body and the cap. The container body has a base and a sidewall with an insert element present inside the container body having a bottom and an insert sidewall, wherein an outer circumferential surface of the insert sidewall is in contact with an inner circumferential surface of the sidewall of the container body. The bottom of the insert element is permeable to moisture and the insert sidewall and the sidewall of the container body are designed to attach the insert element inside the container body. In addition, the container has a desiccant chamber between the bottom of the insert element and the base of the container body for receiving desiccant material.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a container for receiving moisture sensitive goods and a method of manufacturing such a container. 
       DESCRIPTION OF THE PRIOR ART 
       [0002]    Many articles have to be stored and shipped in an environment which is as dry as possible. Therefore, containers are known having the ability to absorb excess moisture inside the container body. In such a way, moisture sensitive goods like medication will normally be protected from moisture until it reaches the end user. However, the consumer must repeatedly open and close the container to access the medication so that moisture loaded air can enter the container each time it will be opened by the user. For this reason it is known in the art to include a desiccating element together with the medication in the container. 
         [0003]    A container is known from EP 0 454 967 A2 which comprises a container body with a container wall and a container bottom, and a layer arranged internally in the container. This layer comprises a desiccant so that the container is suitable for receiving drugs or other goods which have to be kept dry for a long time. If a further desiccant capacity should be needed, EP 0 454 967 A2 further suggests to use a further desiccant element e.g. a desiccant tablet in the plug of the container. 
         [0004]    A desiccant insert gets saturated over time when moisture is ingressing into the vial. As a result of this, desiccant is absorbed close to the external surfaces of the insert so that the external surfaces of the insert become saturated first. This results in an adsorption kinetic that decreases over time because, once the external surfaces or layers close to the surface have been loaded with moisture, additional moisture has to travel a long distance to diffuse to suitable adsorption sites. In other words, it takes a long time to bring humidity down to a layer further remote from the surface of the insert so that, even in case a desiccant insert still has sufficient capacity to adsorb humidity, moisture sensitive goods in the container might take damage before the moisture has been removed from the storage compartment of the container into the insert. 
       DISCLOSURE OF THE INVENTION 
       [0005]    It is the object of the invention to design a container which has improved characteristics when keeping dry goods packaged in the container under all types of exposure to moisture. This object is solved by a container with the features of claim  1 . A method for manufacturing such a container is characterized by the features of claim  11 . Preferred embodiments follow from the other claims. 
         [0006]    The inventive container for receiving moisture sensitive goods comprises a plastic container body and a plastic cap; the cap and the container body being shaped to establish, in the closed state, a leak-proof seal between the container body and the cap. The container body has a base and a sidewall extending upwards from the base. An insert element with a bottom and an insert sidewall is dimensioned to fit into the interior of the container body such that the outer circumferential surface of the insert sidewall is in abutting contact to the inner circumferential surface of the sidewall of the container body. The bottom of the insert element is permeable to moisture and the insert sidewall and the sidewall of the container body are designed to attach the insert element inside the container body. The container has a desiccant chamber between the bottom of the insert element and the base of the container body for receiving a predetermined amount of desiccant material. 
         [0007]    Although reference is made to a sidewall of the container body and an insert sidewall, this wording also covers the possibility to replace the circular cross-section and cylindrical shape of the container sidewall and insert sidewall by a shape with flattened wall sections or a polygonal shape of the sidewall subdividing the sidewall into individual sidewall sections which could be angularly oriented relative to each other. Such geometry with flattened sidewalls or with a polygonal shape could even be advantageous to facilitate the user&#39;s grip. 
         [0008]    Since the outer circumferential surface of the insert sidewall is in abutting contact to the inner circumferential surface of the sidewall of the container body, a double-layered structure of the insert sidewall and the sidewall of the container body is generated. This increases the overall wall thickness. According to a preferred embodiment, the insert sidewall is over a considerable part of its overall outer circumference in abutting contact to the inner circumferential surface of the sidewall of the container body, which means that more than 30% and preferably more than 40% of the outer circumferential surface of the insert sidewall abuts the inner circumferential surface of the sidewall of the container body. According to another preferred embodiment, the inset sidewall only abuts the sidewall in an upper section and a lower section. In this case, the vapor entering through the sidewall can not travel directly to the desiccant chamber but has to penetrate the insert wall first which acts as a further barrier to the ingress of moisture. In other words, a tight sealing is established between the insert sidewall and the container body so that moisture cannot permeate through the sidewalls of the container body and directly into the storage compartment of the container. 
         [0009]    The desiccant material can be a particulate desiccant but also any other type of desiccant like e.g. a desiccant tablet, an injection molded desiccant or a self hardening desiccant wax. 
         [0010]    The inventive container is specifically adapted to all types of exposure to moisture in a plastic container. These are the ingress of moisture when packaging the goods, during shelf-life and during end use. During the packaging of goods, moisture can be trapped in the headspace of the container before closing the cap onto the container body. The same happens during end use when moisture can enter the container during the repeated opening of the cap when removing the products stored within the container. During shelf-life, moisture diffuses through the container wall into the inner space of the container. According to the inventive container, the bottom of the insert element is permeable to moisture so that any moisture ingressing into the vial and reaching the inner space of the vial can directly be transported into the desiccant chamber between the bottom of the insert element and the base of the container body. Therefore, the inventive container has improved adsorption kinetic in comparison to a desiccant insert as known the prior art. Further, the dual wall structure of the insert sidewall and the sidewall of the container body result in a slower moisture vapour transmission rate (MVTR) which is inversely proportional to the thickness of the combined overall wall. In this way, the goods stored within the container are better and longer protected, especially in view of the fact that the effect of moisture ingress through the sidewalls of the container during shelf-life has been underestimated so far. A further advantage is that the material of the insert can be selected in such a way that the barrier properties of the insert element are increased. The insert material can be selected according to specific needs. For example it is possible to select the insert material from an oxygen barrier material such as polyamides or ethylene/vinyl alcohol-copolymer (EVOH) to offer passive protection to both moisture and oxygen. Other examples of suitable and preferred materials include polypropylene, high density polyethylene (HDPE) or low density polyethylene (LOPE) all acting as a barrier to moisture. 
         [0011]    According to a preferred embodiment of the invention, the insert element can also be made of a desiccant polymer. The term “desiccant polymer” covers any materials which are loaded with a desiccant. Suitable materials as well as a process and an apparatus for compounding and injection-moulding desiccant-filled polymers are described in EP 1 970 188 A1, the contents of which are incorporated herein by reference. 
         [0012]    The provision of an insert element made of a desiccant polymer has the advantage that when combined with the desiccant chamber at the bottom of the vial, the provision of an insert element made of a desiccant polymer offers increased desiccant capacity (and therefore increased time of protection for the goods stored inside the container) during shelf-life, and the permeation of vapour through the sidewall can be further reduced because it is trapped in the insert element before reaching the inside of the container. 
         [0013]    According to a preferred embodiment of the invention, the bottom of the insert element is provided with multiple openings. Such openings forming a grid element allow the easy transport of vapour to the desiccant chamber. The openings should be selected such that they effectively withhold the desiccant material even in case of small particles inside the desiccant chamber. 
         [0014]    According to an alternative preferred embodiment of the invention or in addition to the provision of openings, the bottom of the insert element is provided with a membrane or permeable film. Such embodiment also allows an easy transport of vapour from the storage compartment of the container to the desiccant chamber. However, the provision of a membrane or permeable film has the advantage that the goods stored within the storage compartment of the container cannot come in contact with small desiccant particles which could be generated e.g. by abrasion effects. Consequently a dusting of desiccant material into the storage compartment can be successfully prevented. 
         [0015]    According to a preferred embodiment of the invention, the moisture vapour transmission rate (MVTR) of the bottom of the insert element is at least 1.5 times, preferably at least 2 times and most preferably &gt;3 times the moisture vapour transmission rate of the sidewall of the insert element. The MVTR-value as used herein is experimentally determined according to the well-established test procedure. This difference in the MVTR between the bottom of the insert element and the sidewall of the insert element contributes to the desired effect that, especially during shelf-life of the container, any moisture permeating into the storage compartment of the container will be quickly removed therefrom and adsorbed in the desiccant chamber. 
         [0016]    Preferably, there is a locking geometry between the insert sidewall and the sidewall of the container body which serves to securely fix the insert element inside the container. Depending on the specific product to be packaged in the inventive container, it might also be possible to attach specifically adapted insert elements from a kit of different insert elements depending on the desired size of the desiccant chamber or the desired permeability of the bottom of the insert element to moisture. In other words, a single container body could be combined with insert elements having a different geometry to optimize the overall container. 
         [0017]    Preferably, the locking geometry consists of an annular recess in the inner circumferential surface of the sidewall of the container body receiving the insert sidewall. Such geometry can be used to snap in the insert element when it is mounted inside the container body. The insert sidewall can have an annular ridge which is shaped to snap into the annular recess of the inner circumferential surface of the sidewall of the container body. Generally speaking, the locking geometry can be provided in such a way as to form a suitable form lock connection between the sidewall of the container body and the insert sidewall. 
         [0018]    Preferably, a hinge is provided between the body portion and the cap. The hinge between the body portion and the cap of the container can either be a mechanical hinge consisting of a pivot element forming part of the container body to which the cap is rotatably attached, or can be a so-called living hinge according to which the cap is integrally formed with the body portion, and wherein the hinge is formed by a bendable section with a small cross-sectional area between the body portion and the cap. 
         [0019]    When a living hinge is used, the production of the container can be simplified because the container body and the cap are simultaneously produced e.g. in an insert moulding process and no separate production and handling of the cap becomes necessary. 
         [0020]    According to a preferred embodiment of the invention, the seal between the container body and the cap comprises a sealing skirt depending from the top of the cap, which, in the closed state of the cap, sealingly engages with the wall defining the opening of the container body. 
         [0021]    The method for manufacturing a container according to the invention comprises the steps of introducing desiccant material into the container body, inserting the insert element into the container body, fixing the insert element in a defined position relative to the container body and closing the cap on the container body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    In the following, embodiments of the invention will be described with reference to the accompanying drawings in which 
           [0023]      FIG. 1  schematically summarizes the key aspects of the invention; 
           [0024]      FIG. 2  gives a cross-sectional shape of a container according to the invention; 
           [0025]      FIG. 3  shows an enlarged view of detail A as given in  FIG. 2 ; 
           [0026]      FIG. 4  is a view in the direction F-F as shown in  FIG. 2 ; 
           [0027]      FIGS. 5 and 6  are two alternatives of the hinge structure indicated 
           [0028]      FIG. 7  shows a cross-sectional view of the inventive container according to a further embodiment including enlarged details; 
           [0029]      FIG. 8  shows a cross-sectional view of another embodiment of the inventive container including enlarged details; 
           [0030]      FIG. 9  is a view in the direction D-D as sown in  FIG. 8 . 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0031]    In the figures as discussed herein, the same elements will be denoted with the same reference numerals. References to bottom or top or side refer to a container standing upright on a horizontal surface with the cap on top. However, it should be understood that during shipment, storage and use, the container can take all possible orientations. 
         [0032]    The container, generally referenced by reference numeral  10 , houses moisture sensitive goods which are exemplified by a stack of tablets  12 . These goods are stored in a storage compartment  28 . The container  10  comprises a container body  15  and an insert element  14  arranged inside the container body. Further, there is a desiccant chamber  16  formed between the bottom  18  of the insert element and the base  20  of the container body  15 . Preferably, the desiccant chamber  16  is filled with desiccant particles  17 . 
         [0033]    The container body  15  has a sidewall  22  which extends upwardly from the base  20 . At the upper end of the sidewall  22 , there is an opening  25  which is closed by a cap  26  hingedly attached to the container body  15 . 
         [0034]    The insert element  14  has a sidewall  24  and a bottom  18 . The bottom  18  is provided with openings or regions with increased permeability to moisture. The sidewall  24  of the insert element extending upwardly from the bottom  18  of the insert element  14  is shaped so as to snugly fit into the container body. The outer circumferential surface of the sidewall  24  of the insert element abuts against the inner circumferential surface of the sidewall  22  of the container body  15 . 
         [0035]    As is indicated in  FIG. 1 , moisture can enter the container  10  via path M 1  through the cap  26  or, in use, when opening the cap. Further, vapour loaded air can penetrate the sidewall of the container via path M 2 . Further, there is an exchange of vapour from the storage compartment  28  of container  10  to the desiccant chamber  16 . This exchange through the bottom  18  of insert is supported by the high permeability of the bottom  18  as is symbolized by symbol C in  FIG. 1 . The cap  26  is provided as a single-walled structure which already provides a relatively high resistance to the permeation of water vapour. This is symbolized by symbol D in  FIG. 1 . Due to the double wall structure along most of the sidewall of the storage compartment  28 , the permeability of the sidewalls is even smaller than that through the cap  26  as symbolized by symbol E in  FIG. 1 . In this way, the ingress of moisture is generally reduced and, if it should arrive in the storage compartment  28 , the high permeability of the bottom  18  of the insert to the desiccant chamber  16  filled with particulate desiccant material  17  makes sure that the moisture contents in the air within the storage compartment is quickly reduced again to the desired low humidity conditions. 
         [0036]      FIG. 2  schematically shows a cross-sectional view of the container  10  as was schematically given in  FIG. 1 . As can be seen in  FIG. 2 , cap  26  is provided with an opening tab  30  which can be either gripped or pressed by the thumb of a user to more easily open the cap of the container. In the embodiment as shown in  FIG. 2 , the cap  26  is attached to the container body via a hinge  32  which is formed as a mechanical hinge and is shown in more detail in  FIG. 6 . When the cap  26  is in the closed state as shown in  FIG. 2 , an annular sealing skirt depending from the base  27  of cap  26  sealingly engages the upper end of the sidewall  22  of the container body. In addition to this, an outer surrounding rim of the cap  26  can be provided which, as schematically shown in  FIG. 2 , can form a form-lock closure  38  with the upper rim of the sidewall  22  of the container body  15 . 
         [0037]    The insert element  14  is secured to the container body  15  in a suitable way. In the specific embodiment as shown in  FIG. 2 , there is a locking geometry  34  formed between insert element  14  and container body  15 . An enlarged view of the locking geometry  34  can be taken from  FIG. 3 . As can be seen in  FIG. 3 , there is an annular recess  40  formed in the sidewall  22  of container body  15 . The sidewall  24  of insert element  14  has a corresponding geometry which projects into the recess  40  so that a snap-in connection can be formed between insert element  14  and container body  15 . 
         [0038]    An alternative fixation of the insert element inside the container body could be an annular protrusion around the inside of the sidewall  22  of container body  15  onto which the bottom  18  of the insert is placed. However, the fixation as shown in  FIGS. 2 and 3  has the advantage that, depending on the product to be packaged or depending on the climatic environment, differently shaped insert elements could be secured to the container body. Such differently shaped insert elements could provide for a larger or smaller desiccant chamber  16  so that, depending on the specific needs, a different amount of desiccant material could be placed in the container  10 . 
         [0039]    An alternative for increasing the desiccant capacity is the choice of material of the insert element. The insert element could be made of desiccant polymer which further increases the overall capacity of the desiccant material inside the container. However, the different kinetics of adsorption into a desiccant chamber and into an insert element made of desiccant polymer should be considered. 
         [0040]    In this embodiment, the external surface area of the insert, i.e. the overall surface area of the double-walled structure formed by the insert element inside the container body should be at least 30% of the whole surface area of the container, preferably more than 40%. 
         [0041]      FIG. 4  shows the view in direction F-F in  FIG. 2 . It shows the annular sidewall  22  of the container body and the sidewall  24  of the insert element which are in contact with each other leading to a double-walled overall structure of the container  10  in this region. Further, the bottom  18  of insert is shown which is provided with a plurality of holes  44  covered with a membrane or film. In order to stabilize the bottom  18  of the insert element  14 , radially arranged supporting ribs  42  are provided. However, the provision of such supporting ribs  42  and their specific number and arrangement are given by way of example only and any configuration or even the omission of a specific supporting structure is possible as long as the bottom  18  of the insert element  14  has a sufficient stability for carrying the goods to be packaged inside the container  10 . 
         [0042]    The holes covered with a membrane or film could also be provided without a membrane or film element. These holes  44  ease the gas exchange. In contrast thereto, the sidewall  24  of the insert element could be made of a humidity barrier polymer. This leads to a moisture vapour transmission rate (MVTR) of the bottom  18  of insert which is at least 1.5 times, preferably 2 times or even 3 times as high as the sidewall  24  of the insert element  14 . 
         [0043]      FIGS. 5 and 6  show two alternatives how the hinge of the container could be provided. Further, the specific sealing geometry between the sealing skirt  36  and the upper end region of sidewall  22  of the container body  15  is shown. In the example as shown in  FIG. 5 , a so-called living hinge is provided in which the hinge  46  consists a section of plastic material which has a relatively thin cross-section and can be easily bent. Such living hinges between a container body and a cap are known in the art of desiccant containers. Likewise, the provision of a mechanical hinge is also known. In the example as shown in  FIG. 6 , a pivot element  48  is carried by a supporting structure  50  of the container body. The cap is provided with a fulcrum  52  which allows a snap fit connection between the fulcrum  52  of the cap and the pivot element  48  of the container body. Once connected, the cap can be pivoted around the pivot element  48 . 
         [0044]      FIG. 7  shows another embodiment of the inventive container which differs from that as shown in the previous embodiment in two respects. Firstly, the side wall  24  of the insert element is fixed to the annular side wall o the container body in two distinct regions. As demonstrated with the upper and lower boxes also given in enlarged detail views in  FIG. 7 , side wall  24  of the insert element is fixed to side wall  22  of the container body at an upper region and a lower region of the insert element. In both regions as shown in the enlarged detail views in  FIG. 7 , the side wall  24  of the insert element is shaped and dimensioned so as to establish a press-fit connection to the side wall of the container body. Such annular press-fit is advantageous in that, despite of certain manufacturing tolerances, an airtight annular seal between the insert element and the container body is established. However, it is also possible to combine a press-fit connection as shown in  FIG. 7  to a form fit connection as shown in the above  FIG. 2 . Such combination could be useful when the press fit generates high friction forces to be overcome when introducing the insert element and/or when it is desired to indicate the proper positioning of the insert element by providing an audible feedback when the snap-fit-connection has been properly established. 
         [0045]      FIG. 8  shows another embodiment of the invention which, as regards the shape of the container body is very similar to that as shown in  FIG. 7 . The major difference between the previous embodiments and that as shown in  FIG. 8  is the geometry of the insert element which has a rectangular cross-section with slightly rounded side walls. This can be best seen from  FIG. 9  which is a view in the direction of arrows D-D in  FIG. 8 . The insert element according to  FIG. 8  has an inner shape which could be used for storing certain products e.g. test strips or the like which can be kept in a desired order by providing a rectangular inner geometry of the insert element. 
         [0046]    In the embodiment according to  FIG. 8 , there is also established a tight connection between the side wall  24  of the insert element and the annular side wall  22  of the container body. To this end, the side wall  24  of the insert element is provided with an upper flange  54  which has a round circumference which is seated in an annular recess  40  formed in the side wall  22  of the container body  15 . This geometry can also be used to provide a snap-in connection which can be formed between the insert element  14  and the container body  15 . 
         [0047]    In the lower section of the insert  14 , there is provided a second flange  56  which has a circular circumference and can be best seen in  FIG. 9  which demonstrates the four sections of the second flange  56  and its circular circumference corresponding to the inner circumference of the side wall  22  of the container body. The second flange  56  continues in a downward direction in a circular side wall  58  of the insert element which closely follows the inner circumference of the annular side wall  22  of the container body. The wall  58  is provided with a circumferential nose  60  which is shaped and dimensioned so as to form a press fit to the inner circumference of the annular side wall  22  of the container body. 
         [0048]    The button  18  of the insert according to this embodiment is not the lowest part of the insert but has the same function as described in the above embodiments. It delimits the storage compartment  28  and is provided with a high permeability to allow easy communication of moisture to adjacent desiccant chamber  16  filled with particular desiccant material  17 . 
         [0049]    Due to the abutting contact between the insert element and the annular side wall  22  of the container body in two distinct positions, namely the upper region and the lower region of the insert element, moisture penetrating the side wall  22  of the container and entering the free volumes  62  between the container body and the insert element, can not enter the desiccant chamber but has to pass through the wall of the insert element as a further barrier. Such further barrier could be either the flange  54  to enter the storage compartment  28  and into the desiccant chamber  16 , or the second flange  56 , or the side wall  24  of the insert element entering the storage compartment which has easy access to the desiccant chamber. Thus, the embodiment according to  FIG. 8  also provides a double barrier. 
         [0050]    The material of the container and of the insert element can be selected according to the specific requirements of container  10 . It is possible to select the material of the insert such that the barrier properties explained with reference to  FIG. 1  are increased. When the insert is provided as a desiccant entrained polymer, moisture penetrating the sidewall  22  of container body  15  becomes trapped inside the sidewall  24  of insert element and does not diffuse into the storage compartment  28 . Alternatively, the material of the insert could be selected from an oxygen barrier material such as polyamide or EVOH which leads to a passive protection against moisture and oxygen. Other suitable materials are PP, HDPE or LDPE all acting as a barrier to moisture. 
         [0051]    In view of the finding that the penetration of moisture into a desiccant container during its shelf-life has not received sufficient attention so far, the present container combines an increased barrier against the permeation of moisture through the sidewalls into the container and an improved kinetics when removing moisture inside the container resulting in a reduction of the exposure to moisture of products inside the container.