Patent Abstract:
A process for overwrapping a catamenial device such as a tampon includes the steps of providing a substantially cylindrical overwrapper material, inserting a catamenial device into the overwrap material, and closing the open end of the overwrapper material. The overwrapper material has an open end, a closed end, and a first length. The catamenial device has a tapered insertion end, a longitudinal axis, and a length less than the first length, such that the open end of the overwrapper material extends beyond the insertion end of the inserted catamenial device. Concave clamping jaws are applied to the open end of the overwrapper material to urge it toward the longitudinal axis of the catamenial device; to conform portions of the overwrapper material to the insertion end of the catamenial device; and to fold overwrapper material between adjacent clamping jaws to form fins extending outwardly from the conformed portions.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the national stage filing of international application PCT/US2007/081194 filed on Oct. 12, 2007, which claims the benefit of U.S. provisional application 60/829,227 filed on Oct. 12, 2006, both of which are hereby incorporated herewith by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention is related to wrapped cylindrical bodies and in particular catamenial devices useful in absorbing bodily fluids. 
     BACKGROUND OF THE INVENTION 
     Overwrappers for cylindrical bodies and in particular overwrappers for products which can be easily opened but at the same time should be protected from dirt, dust, moisture or other contamination while wrapped such as, for example, catamenial tampons are popular ways to provide individual, portable articles. While the invention will be discussed specifically in terms of catamenial tampons, it will be understood that the problems toward which this invention is directed and their solution applies to many similar products, including, for example, foods, tobacco products and the like. 
     One method and apparatus for closing a packing tube is disclosed in WO 01/36272 (Buzot et al). In this publication, a packing tube is closed around an essentially cylindrical packaged product. The packing tube is projected beyond a free forward end of the product is pressed together and joined by heated clamping jaws to form a first film sheet. The formed first film sheet portion is then folded over and laid onto the outer surface of packing tube at the forward end. Sealing of the folded sheet is accomplished by application of heated dome shaped pressing head. The inner walls surrounding the recess of the heated pressing head melts the folded sheet with the film of the outer surface of the packing tube. Sufficient heat needs to be applied to melt the three layers of film together. Additionally, the heated jaws need to conform to the geometry or curvature of the insertion end of the tampon in order for the melted film to provide a tight fit of the overwrap. 
     New development in catamenial tampons now include those that have covers or fluid transport plates such as those disclosed in US 20050256511, US 20050283128 and WO 2005/112860. In these new types of tampons, by-pass leakage is reduced as the fluid transport plates serve to direct fluid to a fluid storage element. One example of such a tampon is one that includes as fluid transport plates a sheet of apertured film, which covers the insertion portion of the fluid storage element and is attached to the fluid storage element by a longitudinal heat seal. This differs from previous tampons in many ways, including the fact that an apertured film covers the insertion portion of the tampon, which typically has been left uncovered. WO 01/01909 discloses a domed tampon having an absorbent structure substantially enclosed by an apertured film cover that has a nonionic surfactant at least partially applied to the cover. The cover overlaps the domed-shaped introduction end but does not completely cover it. One problem encountered in the type of tampon that has a meltable material at the insertion portion of the tampon relates to providing and heat sealing an overwrap. The heat sealing of the overwrap generally occurs at the insertion end and withdrawal end. When heat is supplied to the overwrap material, the apertured film covering the insertion portion of the tampon is also subjected to the heat. The film may melt, the apertures may close and the film may become attached to the overwrap. 
     What is needed therefore, is a way to seal the overwrap without melting the apertured film covering the insertion portion of the tampon. In particular what is needed is a way to seal a cover or fluid transport element made of a material having a melting point equal to or less than the melting point of the overwrap. One difficulty in overcoming this problem is the geometry of the insertion end of the tampon. This invention solves this problem and provides an overwrapped catamenial device, a method for overwrapping a catamenial device and an apparatus useful for providing this overwrapped catamenial device. 
     SUMMARY OF THE INVENTION 
     The process for overwrapping a catamenial device such as a tampon includes:
         Providing a cylindrical overwrapper having a length greater than the object it will be overwrapping   inserting a catamenial device within the overwrapper such that the overwrapper extends outward from the catamenial device at the insertion end, the cylindrical body having an domed insertion end;   heat sealing the overwrapper at the withdrawal end of the cylindrical body   contacting the extending overwrapper at the domed insertion end with at least three concave clamping jaws, each clamping jaw heated to a temperature minutes;   removing the at least three clamping jaws
 
wherein the overwrap forms a seam over the insertion end such that the overwrap fins are capable of being folded over to conform to the insertion end of the overwrap.
       

     In one aspect of the present invention, an overwrapped catamenial device for absorbing bodily fluids has a cylindrical body having an insertion end and withdrawal end, the insertion end having a dome shape; and a generally cylindrical overwrapper having a first open end and a second closed end. The ends of the overwrap corresponding to the insertion end and the withdrawal end respectively, and the cylindrical body is contained within the cylindrical overwrap. The first open end of cylindrical overwrap extends beyond the dome and forms at least three radial sections extending from a longitudinal axis, which when sealed together form a flat seam which has a curvilinear arc about said dome and a portion extending away from the dome. This may also include folding the seam toward the dome. 
     In another aspect of the invention, an apparatus includes a clamping device, and a finishing former. The clamping device has a plurality of sealing jaws, each jaw having a first end and a second end. The first end is heated to a temperature that causes the overwrap to soften, and it is adapted to receive the cylindrical article such that when the first end of the jaws contacts the cylindrical article the overwrap is molded about the cylindrical article and seals to form a plurality of fins having at least 3 radial sections. The finishing former folds the fins over onto the molded overwrap about the cylindrical article. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  shows a perspective view of an overwrapped tampon of the present invention. 
         FIG. 2  shows a perspective view of a tampon having an insertion end which has a secondary cover. 
         FIG. 3  shows a perspective view of a tubular overwrap before insertion of a tampon. 
         FIG. 4  shows a perspective view of a tubular overwrap sealed at the withdrawal end containing a tampon. 
         FIGS. 5 and 6  show perspective views of tampon having an overwrap sealed by a known method of the prior art. 
         FIG. 7  shows four views of a single jaw of the present invention: 
         FIG. 7A  shows a plan view of the inner face of the jaw from the longitudinal central axis of the apparatus; 
         FIG. 7B  shows a perspective view of the inner face of the jaw; 
         FIG. 7C  shows a side elevation of the jaw; 
         FIG. 7D  shows a perspective view of the side and outer face of the jaw. 
         FIG. 8  shows four views of four jaws forming the apparatus: 
         FIG. 8A  shows a side elevation of two opposed jaws of the apparatus with a tampon disposed in the recess of the apparatus; 
         FIG. 8B  shows a perspective view of the two jaws of  FIG. 8B  in the closed position; and 
         FIG. 8C  shows a perspective view of four jaws in the closed position. 
         FIG. 9  shows five views of four jaws forming an alternative embodiment of the apparatus: 
         FIG. 9A  shows a side elevation of two opposed jaws of the apparatus with a tampon disposed in the recess of the apparatus; 
         FIG. 9B  shows an end elevation of the two jaws of  FIG. 9A  from the view of line B-B; 
         FIG. 9C  shows a perspective view of the two jaws of  FIG. 9B  in the closed position; 
         FIG. 9D  shows a perspective view of four jaws in the closed position; and 
         FIG. 9E  shows an end elevation of the four jaws of  FIG. 9D  from the view of line E-E. 
         FIG. 10  shows a perspective view of tampon after sealing by the clamping jaws of the present invention. 
         FIG. 11  shows a schematic view of a sealed tampon wrapper in a finishing station. 
         FIG. 12  shows a top plan view of one embodiment of the present invention. 
         FIG. 13  shows a top plan view of an alternate embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, illustrated in  FIG. 1  is an example of a wrapped cylindrical body  10  of this invention. The wrapped cylindrical body  10  has an overwrap  20  and specifically a catamenial tampon  30 , which is shown in greater detail in  FIG. 2 . The overwrap  20  is a flexible, tearable, generally moisture and vapor resistant material for the purpose of cleanliness and also to preserve its shape. For the sake of clarity, tear strip  26  is shown only in  FIG. 3 . 
     The tampon  30  has an insertion end  32  and a withdrawal end  34 . The withdrawal end may include a removal string  40 . In  FIG. 2 , the withdrawal string is shown in a wound configuration. During use, the user would unwind the removal string and have it extending away from the tampon. In one embodiment, the insertion end is domed. By domed it is meant that the end of the tampon is not flat and has a rounded or hemispherical shape. In another embodiment, the insertion end has a more flattened geometry. This invention can be adapted to any type of geometry that the insertion end of a tampon may have. 
     As previously stated, uncontrolled sealing of the excess end  22  of the overwrap  20  about the insertion end  32  of the tampon  30  can result in overwrap  20  sticking or being joined to the insertion end  32  of tampon  30 .  FIGS. 5 and 6  illustrate two stages commonly known in the prior art for sealing commercially available tampons, and described, e.g., in Simon et al., U.S. Pat. No. 3,856,143. In this process, a tampon is inserted into an overwrap tube that has one end  24 ′ corresponding to the withdrawal end of the tampon sealed. The excess wrapper  22 ′ at the insertion end is twisted causing the overwrap to conform to the surface of the tampon insertion end and forming a rope-like twisted structure  21 ′. Additional material extends beyond the twist  23 ′ (See  FIG. 5 ). The twisted  21 ′ and excess  23 ′ material is then folded over and conformed to the insertion end  32 ′ of the tampon  30 ′ ( FIG. 6 ). Sufficient heat is applied to the now-closed end  22 ′ of the overwrap  20 ′ to conform it to the introduction end  32 ′ of the tampon  30 ′. In the event that the overwrap material is not heat-sealable, e.g., cellophane, the heat may be necessary to set the excess material  23 ′ in place. In the event that the overwrap material is heat-sealable, it may be necessary to provide sufficient heat to seal the excess material  23 ′ to the rest of the overwrap material at the introduction end  32 ′ of the tampon  30 ′. The result is an uneven surface having multiple melted layers on the insertion portion of the finished wrapped tampon. Too much heat would melt the layers and be conducted into the fibers of the tampon below the layers. In the tampons of the prior art, this was not an issue as the tampons did not have material such as meltable film covering the insertion end. With the new tampons shown in  FIG. 2  and other tampons such as disclosed in Lochte et al. WO 2001/01909, a thermally sensitive material extends further to the introduction end  32  of the tampon  30 . This thermally sensitive material is susceptible to thermal damage during the heat treatment of the overwrap end  22 . 
     The present invention discloses a process, method and apparatus for sealing the overwrap about a tampon that does not result in the overwrap sticking to the tampon or tampon cover. The process also uses less material than the previous processes, which twist or otherwise form a rope-like structure before folding over and sealing to the outer surface. 
     In the present invention, multiple clamping jaws are spring mounted onto a fixed hub. The tampon is moved into position and the clamping jaws close about the insertion end of the tampon, pressing the overwrap toward the central longitudinal axis of the tampon (shown  FIG. 9 ). Each jaw tip contains a heating element, which is used to preheat the jaw. The jaw momentarily contacts the overwrap, causing the overwrap to surround the insertion end of the tampon and be sealed together. The overwrap may extend beyond the insertion end if excess material is used. The jaws are then released, allowing the tampon to move to the folding station where the excess overwrap is folded and sealed back onto the overwrap covering the insertion end. In this invention the required time or temperature to accomplish the sealing and folding is less than the previous methods as there are fewer and more uniform layers or bulk for the heat to penetrate. For example, in one commercial example (O.b.® tampons, available from Personal Products Company, Skillman, N.J., USA) in which the overwrap was twisted into a rope and then folded over, the excess overwrap required was at least ⅝″ of material. The temperature required to finish the insertion end of the overwrap was about 150 to 200° C. for about 0.2 seconds. In the present invention, the length of the excess material may be decreased by at least about 40% (to about ⅜″). The finishing temperature is decreased to about 1250 to 160° C. with substantially the same dwell time. 
     Turning to  FIGS. 7 and 8 , an example of a jaw of the present invention is shown. As shown, jaw  80  includes contacting end  90  and pivoting end  100 . Contacting end  90  includes a sealing surface  92  and heating element (insertable through bore  94 ), which penetrates into the contacting end  90  such that the contacting surface  92  is capable of being heated to a predetermined temperature. Sealing surface  92  is the edge that extends from a concave recess or receiving area region  98  that is of complementary shape to the insertion end of the tampon and includes leading edge  96 . The overwrap is sealed together by the heat and pressure of sealing surface  92  of a first jaw contacting the sealing surface  92  of a second jaw. Leading edge  96  urges the overwrap toward the central axis A-A of the tampon while sealing surface  92  and concave recess  98  form the base of the overwrap seal such that the tubular overwrap conforms to the surface of the insertion end of the tampon. During the process, the excess overwrap material that protrudes beyond the insertion end of the tampon is held in the concave recess  98 . 
     In the present invention, there are at least three clamping jaws and may include more. In one embodiment, it has been found that four clamping jaws form an efficient apparatus that seal the excess overwrap, nicely conforming the overwrap about the insertion end of a tampon. The overwrap that protrudes beyond the tampon is sealed in four quadrants about the central longitudinal axis. As more jaws are used, less overwrap material may be required resulting in less waste. 
     Since sealing surface  92  of the jaw may be preheated before use, the contact time for sealing may be short. In one embodiment, the overwrap material is a polypropylene sheet with a temperature range of about 125° C. to 150° C., for about 0.15 to about 0.3 seconds, preferably about 0.23 seconds. Other materials may have different melting points, so the jaws may be maintained at a temperature appropriate to quickly seal the material used for the overwrap. As the material covering the insertion end of the tampon may have a similar melting point, it is important that the jaws not remain in contact with the overwrap for a long period of time in order to prevent the transfer of heat through the overwrap material. 
     In one embodiment, the overwrap is sealed using four jaws. The sealing surface  92  and the concave recess area  98  of jaw  80  are uniformly aligned at 0° to the longitudinal axis A-A. This allows the overwrap to be sealed symmetrically into radial sections about the longitudinal axis of the tampon and has the excess material  70  extending along the axis. The sealed radial sections (fins  99  as shown in  FIG. 10 ) are then folded to conform to the end surfaces of the overwrap end  22  in a separate finishing station  110  that has a substantially domed recess  112 . Again, the inner sealing surface  114  of this finishing recess  112  may be provided with heating elements to allow the surface to expose the fins  99  to a temperature of about 130-160° C. In this embodiment with substantially longitudinal fins  99 , the finishing may result in squashing of the fins  99  so the material lies close to the surface of the insertion end overwrap (See  FIG. 11 ). 
     In another embodiment, contact surface  92  is positioned at an angle to the longitudinal axis A-A. For example, the angle may be offset sufficient to urge the fins  99  into a pinwheel configuration as shown in  FIG. 12 . Preferably, the offset is at least about 5°, and more preferably at least about 10°, e.g., about 12°. A preferred range is about 10° to about 30°, more preferably about 12° to about 24°. 
     The offset sealing surface  92 ′ forms fins  99 ′ that are at an angle to the longitudinal axis as shown in  FIG. 9 . As can be seen in  FIG. 9E , the parting lines  101  between the sealing surfaces no longer form an “x” as is the case in the straight structure of  FIG. 8 . Instead the inner vertex  103  of the sealing surfaces is offset. This permits them to be folded over in a flatter manner. By using clamping jaws set in an offset angle to the longitudinal axis of the tampon, it is possible to use less heat for finishing the insertion end overwrap as the ultimate thickness of the overwrap is reduced and more uniformly distributed about the insertion end of the package device. 
     Tampon  30  has a compressed, elongated absorbent structure  36 . The absorbent structure may include a fluid storage element having a longitudinal axis. The absorbent structure may also include ribs and grooves such as those described in EP 0 422 660. In one embodiment shown in  FIG. 2 , the absorbent structure is substantially surrounded by a primary cover  50 , which is attached to the sliver prior to compression and a secondary cover  60 , which overlays the primary cover  50 . The secondary cover  60  may form at least one fluid transport element as disclosed in Chase et al., U.S. Ser. No. 10/847,952, published as US 2005-0256511 A1, the disclosure of which is herein incorporated by reference. 
     In one preferred embodiment, the absorbent structure  36  is an absorbent catamenial tampon  30 . Absorbent tampons are usually substantially cylindrical masses of compressed absorbent material having a central axis and a radius that defines the outer circumferential surface of the tampon. Such tampons are disclosed in e.g., Haas, U.S. Pat. No. 1,926,900; Dostal, U.S. Pat. No. 3,811,445; Wolff, U.S. Pat. No. 3,422,496; Friese et al., U.S. Pat. No. 6,310,296; Leutwyler et al., U.S. Pat. No. 5,911,712, Truman, U.S. Pat. No. 3,983,875; Agyapong et al., U.S. Pat. No. 6,554,814; and Chase et al., US 2005-0256511 A1. Tampons also usually include a fluid-permeable cover (which may include or be replaced by another surface treatment) and a withdrawal string or other removal mechanism. The primary cover  50  is fluid-permeable. 
     The absorbent structure can be made of any composition known in the art, such as compressed fibrous webs, rolled goods, foam etc. The storage element can be made of any material known in the art such as cotton, rayon, polyester, superabsorbent material, etc. 
     Fibers may be selected from cellulosic fiber, including natural fibers (such as cotton, wood pulp, jute, and the like) and synthetic fibers (such as regenerated cellulose, cellulose nitrate, cellulose acetate, rayon, polyester, polyvinyl alcohol, polyolefin, polyamine, polyamide, polyacrylonitrile, and the like). 
     Absorbent materials useful in the formation of the absorbent body include fiber, foam, superabsorbent, hydrogels, and the like. Preferred absorbent material for the present invention includes foam and fiber. Absorbent foams may include hydrophilic foams, foams that are readily wetted by aqueous fluids as well as foams in which the cell walls that form the foam themselves absorb fluid. 
     A withdrawal mechanism, such as withdrawal string  40 , is preferably joined to the tampon  30  for removal after use. The withdrawal mechanism is preferably joined to at least the tampon  30  and extends beyond at least its withdrawal end  34 . Any of the withdrawal strings currently known in the art may be used as a suitable withdrawal mechanism, including without limitation, braided (or twisted) cord, yarn, etc. In addition, the withdrawal mechanism can take on other forms such as a ribbon, loop, tab, or the like (including combinations of currently used mechanisms and these other forms). For example, several ribbons may be twisted or braided to provide parallel plates structures. 
     In particular, materials useful for forming the secondary cover  60  (or fluid transport element) may have properties such as thermobondability to provide means to incorporate it into the intravaginal device. A representative, non-limiting list of useful materials includes polyolefins, such as polypropylene and polyethylene; polyolefin copolymers, such as ethylenevinyl acetate (“EVA”), ethylene-propylene, ethyleneacrylates, and ethylene-acrylic acid and salts thereof; halogenated polymers; polyesters and polyester copolymers; polyamides and polyamide copolymers; polyurethanes and polyurethane copolymers; polystyrenes and polystyrene copolymers; and the like. The secondary cover  60  may also be micro-embossed or apertured. Examples of films having apertures include for example, three-dimensional apertured films, as disclosed in Thompson, U.S. Pat. No. 3,929,135, and Turi et al, U.S. Pat. No. 5,567,376, as well as two-dimensional reticulated film, such as that described in Kelly, U.S. Pat. No. 4,381,326. The material used for the secondary cover  60  may have a melting point of less than or equal to the melting point of the overwrap. 
     The compressed tampon  30  is packaged in an overwrap  20  comprising a polymeric film in contact with the secondary cover  60  and containing the tampon  30  under compression. The overwrap  20  is removable from the compressed tampon  30  during use. 
     The overwrap  20  may be chosen from a wide variety of commonly used wrapper materials such as polymeric films or metal foils or even treated papers. The overwrap  20  is rolled about the cylindrical tampon and the end  24  is sealed closed by means of heat sealing, by the use of adhesives or by simply twisting, folding or crimping closed. The transverse edge  28  is sealed closed. The wrapper is to be removed from the tampon by pulling up tab  29  located in the transverse edge  28  of the wrapper to tear the wrapper and free the tampon. 
     EXAMPLE 
     Example 1 
     Tampons were made according to US 2005-0256511 A1 and prepared for packaging according to the present invention. The length of excess overwrap material before sealing was measured to be ¼ inch. After sealing to form fins, the overwrap had an excess length of ⅛ inch. The excess was sealed and folded over at a temperature of about 135° C. for 0.23 seconds without damage to the secondary cover of the packaged tampon.

Technology Classification (CPC): 8