Tampon for feminine hygiene or medical purposes, and process for producing the same

Abstract

A tampon for feminine hygiene or medical purposes comprising a nonwoven cover having at least one, outwardly directed, smooth surface and substantially enclosing a liquid absorbing core wherein the nonwoven cover comprises at least partly thermoplastic, heat-sealable fibers and pressed to the final shape of the tampon. Before the tampon blank is covered with the nonwoven covering web, said web was subject to the use of heat and pressure during the manufacturing of the tampon as to smooth out at least the outer surface of the nonwoven covering web, whilst maintaining the structure of the nonwoven covering web and the absorbency of the tampon. Thereby, it is achieved that the tampon can also be more easily and more comfortably introduced into and withdrawn from a body cavity before and after the days of stronger menstruation or at the occurance of only less vaginal exudation as garment protection.

What is claimed is:  
     
         1 . A tampon for feminine hygiene or medical purposes comprising a nonwoven cover having at least one, outwardly directed, smooth surface and substantially enclosing a liquid absorbing core wherein the nonwoven cover comprises, at least partly thermoplastic, heat-sealable fibers the outwardly directed surface of the nonwoven cover has a coefficient of static friction of less than about 0.4.  
     
     
         2 . The tampon of  claim 1  wherein the caliper of the nonwoven cover is less than about 0.5 mm for four layers of cover.  
     
     
         3 . The tampon of  claim 2  wherein the caliper of the nonwoven cover is less than about 0.2 mm.  
     
     
         4 . The tampon of  claim 1  wherein the coefficient of static friction is less than about 0.3.  
     
     
         5 . The tampon of  claim 4  wherein the coefficient of static friction is less than about 0.26.  
     
     
         6 . A process for producing a tampon for feminine hygiene or medical purposes, comprising the steps: 
 a) continuously feeding an endless, liquid-absorbing sliver made of a mixture of natural and/or artificial fibers, the width of the sliver corresponding approximately to the length of the finished tampon;    b) subdividing the sliver into sections of equal lengths, which are suitable for producing tampons;    c) continuously feeding an endless, nonwoven covering web, which is at least partly composed of thermoplastic fibers and has an essentially open, liquid-permeable structure;    d) cutting the nonwoven covering web into covering web sections;    e) shaping each of the sliver sections into an approximately cylindrical tampon blank with/without the nonwoven covering web section which at least partly forms an outer side;    f) compressing the tampon blank, together with the is nonwoven covering web section at least partly surrounding its surface, radially in relation to its main axis, into the final shape of the tampon, wherein    g) the continuously fed, nonwoven covering web, before it is cut into individual covering web sections, is subjected to a treatment involving heat and pressure, in such a way that at least the outer surface of the nonwoven covering web, which surrounds at least a significant part of the surface of the tampon, is smoothed whilst retaining the characteristics of the nonwoven covering web and the absorption capacity of the tampon.    
     
     
         7 . The process according to  claim 6 , wherein the nonwoven covering web is pretreated at a temperature of about 80-85° C.  
     
     
         8 . The process according to  claim 6 , wherein, during the pretreatment the nonwoven covering web, a pressure of about 0.5-2.5 bar is exerted.  
     
     
         9 . The process according to  claim 6 , wherein the covering web comprises an air-laid, bonded nonwoven that comprises bicomponent fibers having a core of a polymer with a higher melting point and a core covering of a polymer with a comparatively lower melting point.  
     
     
         10 . The process according to  claim 6 , wherein the nonwoven covering web is fastened to the relevant sliver, over part of its area, at a temperature of about 120 to 140° C.  
     
     
         11 . The process according to  claim 10 , wherein the nonwoven covering web comprises a polyethylene fiber material having a melting point of about 130° C.  
     
     
         12 . The process according to  claim 6  wherein the nonwoven covering web has a basis weight of about 11-17 g/m 2 .  
     
     
         13 . The process according to  claim 12 , wherein the nonwoven covering web has a basis weight of about 14 g/m 2 .  
     
     
         14 . The process according to  claim 6  wherein the pretreated nonwoven covering web has a coefficient of friction, measured in a static friction measuring instrument, of less than about 0.4.  
     
     
         15 . The process according to  claim 6 , wherein the endless nonwoven covering web is calendered at a passage speed of about 8-12 m/min.  
     
     
         16 . The process according to  claim 6 , wherein a longitudinal section of the previously smoothed, nonwoven covering web is welded onto the outside of the rear end of a sliver section of specific length, the width of said longitudinal covering web section corresponding approximately to the length of the tampon, the sliver section is then provided with a retrieval string and rolled up on itself to form the tampon blank, so that the nonwoven covering web section extends over the circumference of the tampon blank, which is then pressed into the final shape of the tampon, the nonwoven covering web section, which comprises bicomponent fibers, being sealed onto the sliver section at a length which corresponds approximately to the circumferential length of the tampon blank and, after the sliver section has been rolled up, the unsealed end, projecting beyond the sliver section, is welded to the nonwoven covering web section by applying heat and pressure.  
     
     
         17 . The process according to  claim 16 , wherein, when the nonwoven covering web section is being sealed onto the sliver, heat and pressure are applied more intensely than when the unsealed end, extending freely beyond the outer end of the sliver section, of the nonwoven covering web section is being welded to the nonwoven covering web section sealed onto the sliver section.  
     
     
         18 . The process according to  claim 6 , wherein the central portion of the nonwoven covering web section and one end surface of the tampon blank are positioned adjacent to each other, and in that the remaining portion of the nonwoven covering web section is laid around the entire outer surface of the tampon blank in such a way that the nonwoven covering web section is shaped into a cup enclosing the tampon blank.  
     
     
         19 . The process according to  claim 18 , wherein part of the cup is folded over the other end surface of the enclosed tampon blank.  
     
     
         20 . The process according to  claim 18 , wherein the tampon blank is moved axially towards the nonwoven covering web section in such a way that the remaining portion of the nonwoven covering web section is shaped into a tubular wall of the cup.  
     
     
         21 . The process according to  claim 18 , wherein the central portion of the nonwoven covering web section, which faces away from the tampon blank, is brought into a position aligning with a tubular die plate, the tampon blank then being moved through the die plate, the remaining portion of the nonwoven covering web section being placed in tubular fashion around the outer surface of the moving tampon blank, a cup with a rim extending beyond the other end surface of the tampon blank is formed, and the rim is then folded over the other end surface.