Patent Publication Number: US-2023151555-A1

Title: Natural fiber based lid with undercut

Description:
TECHNICAL FIELD 
     The disclosure relates to a manufacturing component as a first tool in a forming station to form an undercut, a forming station with such a manufacturing component, a forming device comprising such forming station, an endformed lid manufactured with such forming station comprising an undercut and a methode to manufacture such lid with undercut. 
     BACKGROUND 
     It is desirable to protect citizens and the environment from plastic contamination. In particular, disposable plastic products such as packaging materials or plastic cutlery and tableware generate a large amount of waste. In this respect, there is an increasing demand for substitute materials for plastic packaging materials and containers, with which these products can be manufactured from recyclable plastics, materials with a low plastic content or even from plastic-free materials. 
     The idea of using natural fibres instead of classical plastics in the extrusion process has existed at least since the early 1990s, see for example EP 0 447 792 Bl. The raw material basis here, as in most fibre processing methods, is the pulp. In principle, the pulp consists of water, natural fibres and a binding agent such as industrial starch (potato starch) and has a pulpy consistency. 
     Since consumers are interested in a wide variety of nature-compatible products with different sizes, shapes and requirements and do not necessarily demand these in very large quantities, it would be desirable to have a manufacturing process for environmentally compatible molded parts made of natural fibres and a corresponding machine available in order to be able to produce these products (molded parts) effectively, flexibly and reproducibly with good quality. 
     In case of lids for containers, e.g. coffee cups etc., plastic lids commonly comprise an undercut to obtain a secure closure of the container to prevent unintentional lifting of the lid of the container and thus unintentional leakage of the container contents. The undercut is used as a haptic or acoustic feedback to the user when closing the container with the lid hearing or feeling a click, when the lid is arranged on top of the container and the undercut snaps onto the container in a safe position. In case of using lids made from natural fibres, the preparation of such undercut is difficult. Tool technology for forming machines to manufacture lids with undercuts providing such feedback reliable are not available yet. Therefore lids made from natural fibre material cannot replace plastic lids without loss of security. 
     Therefore, it is a demand to provide a tool technology enabling to manufacture lids from natural fibre materials providing the common safety level for closing container with such lids. 
     SUMMARY 
     It is an object of the present disclosure to provide a tool technology enabling to manufacture lids from natural fibre materials providing the common safety level for closing containers with such lids. 
     The object is solved by a manufacturing component to be used as a first tool in a forming station at least for endforming a preformed lid made from a material comprising natural fibres, the preformed lid comprising a top part and a side part circumferencing the top part, where the manufacturing component is adapted to contact an outer side of the preformed lid to endform the preformed lid by exerting a first movement in axial direction along a center axis of the manufacturing component and a later second movement in a second direction towards the side part of the preformed lid, where multiple side forming elements of the manufacturing component are arranged to exert the second movement applying an outer pressure onto an outer side of the side part to form an undercut into the side part. 
     Such undercut is necessary to provide a reliable haptic or acoustic feedback to users when closing containers such as coffee cups etc. informing the user about an established and safe closure of the container. Containers containing dangerous content, e.g. hot liquids, should be closed safety in order to protect the user. After having received the feedback provided by the undercut, the user can be sure not to get into contact with the dangerous content in an unintended way, e.g. by spilling hot coffee on their fingers. 
     The term “undercut” denotes a suitable bended or curved shape within a component (the lid) interacting with another component (e.g. a container) when connecting both components (container and lid forming a closed container) together. The undercut engages with a corresponding counter-shape of the other component or snaps behind a bead or edge of the other component in order to securely fix one component mechanically to the other component. The undercut within the lid may have different shapes within the scope of the present disclosure depending on the properties of the corresponding container. 
     The second movement executed by the side forming elements is directed towards the side part of the preformed lid, in which the undercut shall be introduced. Preferably the second movement is directed perpendicular to the outer side of the side part. Since the side part has a shape surrounding the top of the lid, the side forming elements have a similar shape in order to preferably fully contact the side part with the inner side of the side forming elements. In case of a circular shaped lid, the second movement is directed radially to the center axis of the manufacturing component, which is the symmetric axis of the circular lid. 
     The term “to endform the lid” denotes the particular manufacturing step to finalize the shape of the lid. Endforming does not exclude that additional production steps not changing the shape of the lid may follow after having endformed the lid. Endforming does also not limit or exclude any production step before the endforming takes place. For endforming the lid, the lid might be provided as already existing preform or the materials of the lid may provided in other forms, e.g. as sheet material and will be preformed in the preforming station or directly within the forming station. 
     The lid may have any suitable shape to close the corresponding container, which also may have any suitable shape. Lids have a top part and a side part circumferencing the top part. Common lids may be circular or rectangular. However any other shape of lids and containers may also be possible. The manufacturing component and the forming station according to the present disclosure are suited to make undercuts into side parts of lids not limited to a particular shape of the lids as well as not limited to a particular shape of the undercuts. The material of the lid comprises natural fibres. The material may comprise additional other material, e.g. applied as a composite material together with the natural fibres or applied as an additional layer on top of the natural fibre material. Such layer or multiple layers may be applied onto the outer side or the inner side of the lid. In an embodiment the lid is fully covered by such layers. In an embodiment the lid may consist of natural fibre material. In any case the natural fibre material may be impregnated with other material to increases a resistance or impermeability at least against liquids and/or moisture. 
     The manufacturing component is used as a tool in a forming station. Here the manufacturing component can be an upper or lower tool in the forming station depending on the particular forming station and forming process. 
     The term “moving one tool on top of another tool” does not imply any moving direction, especially not that the moved one tool is arranged above the other tool. This term simply denotes, that both tools are moved together at least during forming the undercut. 
     The manufacturing component according to the present disclosure provides a tool technology enabling to manufacture lids from natural fibre materials providing the common safety level for closing containers with such lids by forming undercuts into the endformed lids. 
     In an embodiment the side forming elements are arranged around the center axis, wherein the side forming elements are suitably shaped to provide a free space between adjacent side forming elements prior to exerting the second movement. The arrangement around the center axis enables the side forming elements to introduce an undercut along the whole side part of the side of the preformed lid. The free spaces enable all side forming elements to apply a defined outer pressure to the whole side part of the preformed lid, since the side forming elements have enough moving freedom to fully contact the side part without being hampered due to mechanical contact between neighbored side forming elements. 
     In another embodiment the manufacturing component comprises at least three side forming elements, preferably four to six side forming elements, more preferably seven to nine side forming elements, even more preferably ten side forming elements. With increasing number of side forming elements the applied outer pressure will be more homogeneous around the side part of the preformed lid. However the complexity of the mechanical construction to perform the second movement with all side forming elements will increase with the number of side forming elements. The above specified numbers of side forming elements are a good compromise between homogeneity of the applied outer pressure and the effort to build and maintain the mechanical construction to perform the second movement. 
     In another embodiment in case of a circular preformed lid with circumferencing side part, the second direction is a radial direction towards the center axis and the side forming elements are arranged circularly around the center axis. 
     In another embodiment the side forming elements each comprises an inner side directed towards the outer side of the side part of the preformed lid, where each inner side has a contour adapted to a desired shape of the undercut. Preferably the side forming elements are suitably shaped to provide an undercut circumferencing the side part of the preformed lid. An undercut which is located along the whole side part of the lid will provide a very safe closure of the container. A circumferenting undercut will provide a more secure closing of the container. 
     In another embodiment at least a part of the surfaces of the manufacturing component intended to be in contact with the natural fibre material of the preformed lid is made of a material with decreased friction or adhesion properties. Friction or adhesion can be reduced by smoothing the surface of the manufacturing component. For this purpose the manufacturing component might be established from a material, which surface can be polished. Alternatively the manufacturing component can be at least locally covered with a smooth coating. Preferable at least the inner side of the side forming elements are made of the material with decreased friction or adhesion properties or coated with at least one layer of this material. 
     The present disclosure also relates to a forming station comprising first and second tools at least for endforming a preformed lid, where a manufacturing component according to the present disclosure is the first tool, preferably an upper tool, and the second tool, preferably a lower tool, is adapted to at least carry the preformed lid, where at least one motor system is adapted to move the first tool on top of the second tool with the preformed lid inbetween in a first movement and in a later second movement to move the side forming elements of the first tool towards the side part of the preformed lid applying an outer pressure onto an outer side of the side part to form an undercut into the side part. 
     The forming station according to the present disclosure provides a tool technology enabling to manufacture lids from natural fibre materials providing the common safety level for closing containers with such lids by forming undercuts into the endformed lids. 
     The second tool acts as a counter part for the first tool when forming the undercut. In an embodiment the second tool is suitably shaped to at least support an inner side of the side part during application of the outer pressure to the outer side of the side part by the side forming elements, so that the undercut is reliably formed by the side forming elements. 
     In another embodiment the second tool comprises a counter part to support the inner side of the side part, where a contour of the counter part is adapted to a desired shape of the to be form undercut at the inner side of the side part. With this counter part, the outer pressure to form the undercut can be applied in a more defined and reproducible process compared to a tool not comprising such counter part. 
     In another embodiment the counter part is divided in movable counter part elements, which are adapted to move towards the center axis in order to enable an easy release the endformed lid after being endformed. 
     In another embodiment the forming station is adapted to receive the preformed lid from a preforming station. Here, the degree of automation of the production process is increased also resulting in a more effective and faster process. 
     In another embodiment the forming station is adapted to preform the lid prior to endforming the preformed lid. Here, the number of required process stations is reduced enabling to provide a more compact process. 
     In another embodiment the material is a provided as sheet material for preforming the lid. A sheet material enables a quasi continuous production process. The material in form of sheet material can be handled more easy and less space consuming compared to a paper pulp process. In another embodiment the sheet material is provided directly to the forming station, where the forming station preforms and endforms the lid. 
     In another embodiment both first tool and second tool are moved by the motor system to place the upper tool on top of the second tool, preferably both tools are moved simultaneously. Moving both components result in a decrease opening and closing time of first and second tools of the forming station. 
     The present disclosure further relates to a forming device comprising a forming station according to the present disclosure and a preforming station, where the preforming station is adapted to preform a lid from a material comprising natural fibres and the forming station is adapted to receive the preformed lid from the preforming station and to provide an endformed lid comprising an undercut within a side part of the endformed lid. The preforming station as part of the forming device allows to control both production steps, the preforming and the endforming, in one device allowing a better process control and better endforming quality. 
     The forming device according to the present disclosure provides a tool technology enabling to manufacture lids from natural fibre materials providing the common safety level for closing containers with such lids by forming undercuts into the endformed lids. 
     In an embodiment the forming device further comprises a transfer station transporting the preformed lid to the forming station for enforming the preformed lid. This also increases the degree of automation of the production process further resulting in a more effective and faster process. In a preferred embodiment the forming device also comprises a stacking station to stack the endformed lids outputed from the forming station. 
     In another embodiment the material is provided as a sheet material to the preform station to preform the lid from the sheet material. A sheet material enables a quasi continuous production process. The material in form of sheet material can be handled more easy and less space consuming compared to a paper pulp process. 
     In another embodiment the preforming station applies a paper pulp process to preform the lid. The use of natural fibres to form products is a long existing demand. Natural fibre products are available on the market today, however quality and performance do not meet the requirements of containers for food products The raw material basis here, as in most fibre-processing processes, is the pulp. In principle, the pulp consists of water, natural fibres and a binding agent such as industrial starch (potato starch) and has a pulpy consistency. The term “pulp” refers to fluid masses containing fibres, here the environmentally friendly degradable fibre material. The term “liquid” here refers to the aggregate state of the pulp, whereby the liquid pulp comprises the environmentally degradable fibre material in the form of fibres. The fibres can be present as individual fibres, as fibre structures or fibre groups consisting of several coherent fibres. The fibers represent the fiber material regardless of whether they are present in the pulp as individual fibers, as fiber formations or fiber groups. The fibres are dissolved in the liquid solution in such a way that they float in the liquid solution with as equal a concentration as possible regardless of location, for example as a mixture or suspension of liquid solution and fibre material. 
     The present disclosure further relates to an endformed lid made of a material comprising natural fibres, the endformed lid comprises a top part and a side part circumferencing the top part and an undercut in the side part formed by a forming station according to the present disclosure, preferably the undercut circumferences the side part. 
     The material of the endformed lid comprises natural fibres. The material may comprise additional other material, e.g. applied as a composite material together with the natural fibres or applied as an additional layer on top of the natural fibre material. Such layer or multiple layers may be applied onto the outer side or the inner side of the lid. In an embodiment the endformed lid is fully covered by such layers. The layers or additive material to the natural fibre material may be applied before or after endforming of the lid. In an embodiment the endformed lid may consist of natural fibre material. In any case the natural fibre material may be impregnated with other material to increases a resistance or impermeability at least against liquids and/or moisture. 
     The endformed lid according to the present disclosure results from a tool technology enabling to manufacture lids from natural fibre materials providing the common safety level for closing containers with such lids by forming undercuts into the endformed lids. 
     The present disclosure further relates to a method to provide endformed lids made of a material comprising natural fibres with a forming station according to the present disclosure with a manufacturing component according to the present disclosure as a first tool and a second tool, where a preformed lid comprises a top part and a side part circumferencing the top part, comprising the steps of:
         providing a preformed lid;   performing a first movement in axial direction along a center axis of the manufacturing component at least with the first tool to contact an outer side of the lid;   performing a following second movement in second direction with multiple side forming elements of the first tool moved towards the center axis of the lid to apply an outer pressure onto an outer side of the side part of the lid to form an undercut into the side part to establish the endformed lid; and   outputting the endformed lid with the undercut in the side part.       

     The method according to the present disclosure allows to use a tool technology enabling to manufacture lids from natural fibre materials providing the common safety level for closing containers with such lids by forming undercuts into the endformed lids. 
     In an embodiment the method further comprises the step of preforming the material in a preforming station to provide the preformed lid. 
     In another embodiment the method further comprises the steps of
         transferring the preformed lid from the preforming station to the forming station with a transfer station; and/or   stacking the endformed lids outputed from the forming station by a stacking station.       

     In another embodiment the method further comprises the step providing the material as a sheet material to the preforming station for the preforming step. 
     In another embodiment of the method, the step of preforming the material applies a paper pulp process. 
     In another embodiment of the method, the step of preforming the material might be executed in the forming station prior to endforming the preformed lid, where the forming station can perform the function of the preforming station, preferably the material is provided as a sheet material to the forming station. The forming station may preform the lid in a different way compared to the process applied in the preforming station or applied in any other station for preforming the lid. 
     It should be pointed out that in the context of the patent application indefinite articles and indefinite numerical data such as “one . . . ”, “two . . . ” etc. should normally be understood as minimum data, i.e. as “at least one . . . ”, “at least two . . . ” etc., unless it is clear from the context or the specific text of a certain passage that only “exactly one . . . ”, “exactly two . . . ” etc. are meant. 
     It is understood that the embodiments described above or features thereof may also be combined with each other in any combinations deviating from the claims and their back references in order to provide solutions to the above task within the scope of the present disclosure. 
     Components, which are at least essentially identical in the individual figures with respect to their function, are marked with the same reference signs, whereby the components do not have to be numbered and explained in all figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG.  1    depicts a forming station with manufacturing component as upper tool according to some embodiments. 
         FIG.  2    depicts an endformed lid with undercut according to some embodiments. 
         FIG.  3    depicts a side forming elements (a) before the second movement and (b) after the second movement for generating the undercut; 
         FIG.  4    depicts a schematic view of (a) the counter part of the second tool and (b) the forming station in a side view; 
         FIG.  5    depicts a forming device according to some embodiments. 
         FIG.  6    depicts a method to provide endformed lids made of natural fibre material according to some embodiments. 
     
    
    
     DETAILED EMBODIMENTS 
       FIG.  1    shows a forming station  10  comprising first and second tools  1 ,  20  at least for endforming a preformed lid  100  made from a material M comprising natural fibres, where the first tool  1  is an upper tool, and the second tool  20  is a lower tool adapted to at least carry the preformed lid  100 , where at least one motor system  30  is adapted to move the first tool  1  on top of the second tool  20  with the preformed lid  100  inbetween in a first movement FM and in a later second movement SM to endform the preformed lid  100  to comprise an undercut  140 . A manufacturing component  1  establish the first tool  1  in the forming station  10 . The preformed lid  100  comprising a top part  130  and a side part  110  circumferencing the top part  130 . The manufacturing component  1  (first tool) is adapted to contact an outer side  110  of the preformed lid  100  to endform the preformed lid  100  by exerting a first movement FM in axial direction along a center axis R of the manufacturing component  1 . Here, both first tool  1  and second tool  20  are moved by the motor system  30  to place the upper tool  1  on top of the second tool  20 , preferably both tools  1 ,  20  are moved simultaneously. Later a second movement SM in a second direction towards the side part  120  of the preformed lid  100  is executed by the manufacturing component  1 . Multiple side forming elements  2  of the manufacturing component  1  are arranged to exert the second movement SM applying an outer pressure PA onto an outer side  110  of the side part  120  to form an undercut  140  into the side part  120 . Here, at least a part of the surfaces of the manufacturing component  1  intended to be in contact with the material M of the preformed lid  100  is made of a material with decreased friction or adhesion properties. The second tool  20  is suitably shaped to at least support an inner side  150  of the side part  120  during application of the outer pressure to the outer side  110  of the side part  110  by the side forming elements  2 , so that the undercut  140  is reliably formed by the side forming elements  2 . The forming station  10  is adapted to receive the preformed lid  100  from a preforming station  50 . Alternatively the forming station  10  might be adapted to preform the lid  100  prior to endforming the preformed lid  100 . The material M might be a provided as sheet material for preforming the lid  100 . 
       FIG.  2    shows an endformed lid  100 ′ with undercut  140  according to some embodiments made of a material M comprising natural fibres. The endformed lid  100 ′ comprises a top part  130  and a side part  110  circumferencing the top part  130  having an outer side  110  and an inner side  150 . The outer side  110  denotes the outer side of the top of the lid as well as the side part  120  of the lid  100 ′. The lid  100 ′ further comprises an undercut  140  in the side part  120  formed by a forming station  10  according to the present disclosure. Preferably the undercut  140  circumferences the side part  120 . The numerals for side part  120 , the outer side  110 , the inner side  150  and the top part  130  shown here in relation to the endformed lid  100 ′ also applies to the preformed lid  100 . 
       FIG.  3    shows side forming elements  2  ( a ) before the second movement SM and (b) after the second movement SM for generating the undercut  140 . The side forming elements  2  are arranged around the center axis R, wherein the side forming elements  2  are suitably shaped to provide a free space  21  between adjacent side forming elements  2  prior to exerting the second movement SM, see  FIG.  3   a   . The manufacturing component  1  here comprises four side forming elements  2  arranged symmetrically to each other. Other embodiment may have different numbers of side forming elements  2 . In this example the preformed lid  100  is circular with circumferencing side part  110 , the second direction for the second movement SM is a radial direction towards the center axis R and the side forming elements  2  are arranged circularly around the center axis R. The side forming elements  2  each comprises an inner side  2   i  directed towards the outer side  110  of the side part  120 , where each inner side  2   i  has a contour adapted to a desired shape of the undercut  140 , where the side forming elements  2  are suitable shaped to provide an undercut  140  circumferenting the side part  120  of the preformed lid  100 . At least the inner side  2   i  of the side forming elements  2  might bee made of the material with decreased friction or adhesion properties or coated with at least one layer of this material. 
       FIG.  4    shows a schematic view of (a) the counter part  40  of the second tool  20  and (b) the forming station  10  in a side view. The second tool  20  comprises a counter part  40  to support the inner side  150  of the side part  120  of the preformed lid  100 , where a contour of the counter part  40  is adapted to a desired shape of the to be form undercut  140  at the inner side  150  of the side part  120 . The counter part  40  is divided in movable counter part elements  45  (see  FIG.  4   a   ), which are adapted to move towards the center axis R in order to release the endformed lid  100 ′ from the forming station  10  after being endformed. 
       FIG.  5    shows a forming device  80  according to some embodiments comprising a forming station  10  according to the present disclosure and a preforming station  50 . The preforming station  50  is adapted to preform a lid  100  from a material M comprising natural fibres. The forming station  10  is adapted to receive the preformed lid  100  from the preforming station  50  and to provide an endformed lid  100 ′ comprising an undercut  140  within a side part  120  of the endformed lid  100 ′. The forming device  80  further comprises a transfer station  60  transporting the preformed lid  100  to the forming station  10  for enforming the preformed lid  100  and a stacking station  70  to stack the endformed lids  100 ′ outputed from the forming station  10 . Here, the material M is provided as a sheet material to the preform station  50  to preform the lid  100  from the sheet material. Alternatively the preforming station  50  may apply a paper pulp process to preform the lid  100 . 
       FIG.  6    shows a method  200  to provide endformed lids  100  according to some embodiments made of material M comprising natural fibres with a forming station  10  according to the present disclosure with a manufacturing component  1  according to the present invention as a first tool and a second tool  20 , where a preformed lid  100  comprises a top part  130  and a side part  110  circumferencing the top part  130 , comprising the steps of providing  210  the preformed lid  100 ; performing  220  a first movement FM in axial direction along a center axis R of the manufacturing component  1  at least with the first tool  1  to contact an outer side  110  of the lid  100 ; performing  230  a following second movement SM in second direction with multiple side forming elements  2  of the first tool  1  moved towards the center axis R of the lid  100  to apply an outer pressure PA onto an outer side  110  of the side part  120  of the lid  100  to form an undercut  140  into the side part  120  to establish the endformed lid  100 ′; and outputting  240  the endformed lid  100 ′ with the undercut  140  in the side part  120 , eventually followed by stacking  270  the endformed lids  100 ′ outputed from the forming station  10  by stacking station  70 . In an embodiment the method comprises the step of preforming  250  the material M in a preforming station  50  to provide the preformed lid  100  together with the steps of transferring  260  the preformed lid  100  from the preforming station  50  to the forming station  10  with a transfer station  60 . Here, the material M might be provided  280  to the preforming station  50  as a sheet material for the preforming step  250 . Alternatively the step of preforming  250  the material M may apply a paper pulp process. In another alternative the step of preforming  250  the material M might be executed in the forming station  10  prior to endforming the preformed lid  100 , where the forming station  10  performs the function of the preforming station  50 . In this case the material M is provided as directly, e.g. as sheet material  280 , to the forming station  10  for performing  220  a first movement in axial direction with the upper tool. 
     At this point, it should be explicitly pointed out that features of the solutions described above or in the claims and/or figures may also be combined, if necessary, in order to be able to implement or achieve the explained features, effects and advantages in a corresponding cumulative manner. 
     LIST OF NUMERALS 
     
         
           1  manufacturing component (first tool, e.g. upper tool) according to the present disclosure 
           2  side forming elements of the manufacturing component 
           2   i  inner side of the side forming element 
           21  free space between adjacent side forming elements 
           10  forming station according to the present disclosure 
           20  second tool, e.g. lower tool 
           30  motor system of the forming station 
           40  counter part of the second tool, e.g. a ring part of the second tool 
           45  counter part elements 
           50  preforming station 
           60  transfer station 
           70  stacking station 
           80  forming device according to the present disclosure 
           100  preformed lid 
           100 ′ endformed lid according to the present disclosure 
           110  outer side of the lid, e.g. outer side of the side part of the lid 
           120  side part of the lid 
           130  top part of the lid 
           140  undercut 
           150  inner side of the side part of the lid 
           200  method to endform a lid made of natural fibre material with a forming station according to the present disclosure 
           210  providing a preformed lid 
           220  performing a first movement in axial direction with the upper tool 
           230  performing a following second movement in radial direction with multiple side forming elements of the upper tool 
           240  outputting the endformed lid 
           250  preforming the lid in a preforming station 
           260  transferring the lid from the preforming station to the forming station with a transfer station 
           270  stacking the endformed lids outputed from the forming station by stacking station 
           280  providing the natural fibre material as sheet material 
         D depth of undercut 
         R center axis of the lid 
         PA axially directed pressure 
         M natural fibre material 
         FM first movement 
         SM second movement 
         RM movement to release the endformed lid from the second tool