Abstract:
A pants type disposable undergarment is provided which is equipped with an elasticized side panel. The side panel is elasticized with elastic film. The elastic film is attached to a nonwoven layer. The elasticized nonwoven layer is then split into two sections. A portion of the elasticized nonwoven layer is then ultrasonically cut to the desired configuration. The elastic film does not traverse the crotch region. Also provided are methods for producing such disposable undergarments.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention related to disposable undergarments and more particularly, a pants type undergarment which is equipped with elastic film which does not traverse the crotch region, and to a method of producing such undergarments.  
         [0002]     Disposable undergarments of the children&#39;s training pant type, or of the adult incontinence type, are generally made up of two nonwoven layers of material with elastic strands of material placed between the two nonwoven layers of material thus creating an elastic web laminate. The layers of material are continuous sheets of material that are eventually cut into individual undergarments lengths. The elastic strands may be arranged and cut so that specific areas of the undergarment are free of elastic tension or forces.  
         [0003]     Many patents describe methods of putting elastic in the leg hole area of a undergarment. For example, U.S. Pat. Nos. 5,745,922, 5,188,627, 5,660,657, 5,643,396, 5,634,917 and 5,660,657. Still, the problem remains of efficiently and securely placing elastic in other areas of the undergarment besides the leg hole areas. Securing elastic strands around the back and front waists, for example, in a secure and systematic manner is also an element of disposable undergarment design that has not been perfectly addressed in the prior art.  
       SUMMARY OF THE INVENTION  
       [0004]     It is a principal object of this invention to provide an improved method of producing a pants type undergarment and to provide the resultant improved undergarment. As compared to previous designs and processes, the present invention results in less material use, a better visual appearance of the final product, and a more reliable process.  
         [0005]     In accordance with this invention, elastic film is stretched, relaxed, and then restretched before being applied to a section of nonwoven fabric material. The elastic film section is then split into two sections and each section is cut before being applied to the undergarment chassis. The undergarment chassis is formed by splitting an indicator patch into two sections and applying the indicator patch section to a nonwoven fabric material.  
         [0006]     In accordance with another aspect of the invention, once the elastic film sections are attached to the undergarment chassis an absorbent insert is also attached to the undergarment chassis. The absorbent insert is retained on the undergarment chassis by either folding the undergarment chassis material edges over or adhesively applying an additional layer of nonwoven material to the undergarment chassis.  
         [0007]     In a first embodiment of the invention, the elastic film sections are cut in such a manner that additional waistband elastic is used, but leg hole elastic is not used. The method of this embodiment includes the additional step of adding waistband elastic to the undergarment chassis.  
         [0008]     A second embodiment of the invention involves a similar method, but differs in that the elastic film is cut in a different configuration. In this embodiment the step of including leg elastic is added method described above.  
         [0009]     A third embodiment of the invention is similar to the first embodiment, but differs in that the elastic film is cut in a different configuration. In the embodiment the step of adding a waistband elastic is eliminated. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective exploded view of an undergarment produced according to the present invention.  
         [0011]      FIG. 2   a  is a top planar view of an undergarment produced according to the first embodiment of the present invention.  
         [0012]      FIG. 2   b  is a top planar view of a side panel assembly of embodiment shown in  FIG. 2   a.    
         [0013]      FIG. 3   a  is a top planar view of an undergarment produced according to the second embodiment of the present invention.  
         [0014]      FIG. 3   b  is a top planar view of a side panel assembly of embodiment shown in  FIG. 3   a.    
         [0015]      FIG. 4   a  is a top planar view of an undergarment produced according to the third embodiment of the present invention.  
         [0016]      FIG. 4   b  is a top planar view of a side panel assembly of embodiment shown in  FIG. 4   a.    
         [0017]      FIG. 5  is a diagrammatic illustration of a method of producing undergarments according to the present invention.  
         [0018]      FIG. 6  is a cross-sectional view of an undergarment produced according to the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.  
         [0020]      FIG. 1  shows an exploded perspective view of an undergarment  10  produced according to the present invention. The undergarment  10  includes a chassis  12 , indicator patch sections  14 , side panels  16  including stretch elastic film sections  18 , and waistband elastic  20 .  
         [0021]      FIG. 2   a  shows a top view of an undergarment  10  according to the first embodiment of this invention.  FIG. 2   b  shows a side panel  16  of the undergarment  10  of the first embodiment. The stretch elastic film sections  18  are configured such that leg hole elastic is not necessary.  
         [0022]      FIG. 5  shows a diagrammatic illustration of an embodiment of the present invention. A system for producing the chassis assembly for disposable undergarments is shown. A roll or layer of chassis nonwoven material  12  is fed into the system. A roll of indicator patch material  14  is unwound and fed through a slitting and spreading station  22  to slit the indicator patch material  14  into two sections and position the separate indicator patch sections  14   a  and  14   b  on the process lines. Adhesive applicators  24   a  and  24   b  applies adhesive to each of the indicator patch sections  14   a  and  14   b  respectively. Each of the separate indicator patch sections  14   a  and  14   b  is then applied to the chassis nonwoven material  12  by rollers  26   a  and  26   b  respectively. This forms the chassis assembly  28 .  
         [0023]     At the same time, a roll of elastic film  18  is unwound and fed into the system. A plurality of rollers  30  stretches the elastic film  18  to 300% of its original length and then relaxes the elastic film  18  to 150% of its original length. The elastic film  18  is then perforated for breathability at a perforating station  32 . The perforation can be in any pattern; however the preferable pattern is slashes at 45 degrees to the direction of the elastic film  18 , for maximum breathability when the elastic film  18  is stretched. The elastic film  18  is then stretched again by a system of chilled rollers  34  to 300% of its original length.  
         [0024]     A roll of side panel nonwoven material  16  is fed into the system. An adhesive applicator  36  applies an adhesive coating to the side panel nonwoven material  16 . The elastic film  18  is then joined to the side panel nonwoven material  16  by rollers  38  to form the side panel assembly  40 . Any suitable adhesive that will sufficiently adhere the elastic film  18  to the side panel nonwoven material  16  may be used; however, a hot melt applicator is preferable. The design of the side panel nonwoven material  16  and the elastic film  18  should determine where and how the adhesive applicator  36  applies and adhesive to the side panel nonwoven layer  16 , and any arrangement should not be considered a limiting factor.  
         [0025]     The side panel assembly  40  is then fed through a slitter  42  to form two separate side panel assemblies  40   a  and  40   b . Ultrasonic cutting means  42   a  and  42   b  are used to cut only the elastic film  18  in the character patch area  13  in each of the side panel assemblies  40   a  and  40   b . Additionally, a portion of each side panel assembly  40   a  and  40   b  near the waistband section of the side panel assembly is cut away. This portion could be cut by any of several cutting means such as a perforated die cuts or ultrasonic cutting means.  FIG. 4   a  shows an undergarment  10  exemplifying a first embodiment of the present invention.  FIG. 2   b  depicts the configuration of one of the side panel assembly  40   b  after being cut. The side panel assemblies  40   a  and  40   b  are mirror images of each other. The adhesive which was selectively applied above is not applied in the character patch area or the waist band area. Vacuum anvils  44   a  and  44   b  remove the unwanted elastic film  18  section.  
         [0026]     The side panel assemblies  40   a  and  40   b  are then adhesively attached to the chassis assembly  28  by adhesive application devices  46   a  and  46   b  along with rollers  48   a  and  48   b . The entire undergarment chassis  50  is brought into the main machine for further processing.  
         [0027]     An adhesive applicator  52  applies adhesive to the undergarment chassis  50 , then waistband elastic  20  is applied by rollers  54 . As seen in  FIG. 2   a  waist elastic  20  is applied to opposite sides of the undergarment chassis  50 , such that when the undergarment chassis  50  is folded together and the side seams are formed the waist band elastic  20  will entirely encircle the waist area of the undergarment  10 .  
         [0028]     The undergarment chassis  50  is now further processed according to known means. An adhesive applicator selectively applies an adhesive to the chassis assembly. A succession of absorbent inserts  52  are picked up at a supply station by vacuum heads of a pad supplying/turning device. The absorbent inserts  52  are known in the art and are generally comprised of various absorbent materials contained within a nonwoven material cover. The absorbent inserts  52  are rotated 90 degrees and applied, successively, to the crotch areas of the undergarment chassis by a transfer roll where they are attached adhesively to the inside of the undergarment chassis  50 .  
         [0029]     An adhesive applicator applies an adhesive to the undergarment chassis. The undergarment chassis  50  is then folded over on its edges to secure the absorbent insert  52 . Alternatively, an additional cover nonwoven material strip could be utilized in lieu of folding the undergarment chassis  50  edge over.  FIG. 6  is a cross-sectional view of an undergarment  10  produced according to the first embodiment of the present invention including an absorbent insert  52 .  
         [0030]     The undergarment chassis  50  will proceed for further modifications, such as adding decorative material or cutting of leg holes, if not previously cut, and folding, sealing and severing the web into individual undergarments.  
         [0031]     A second embodiment of an undergarment  110  exemplifying the present invention is shown in  FIG. 3   a . The undergarment  110  of the second embodiment is substantially similar to the undergarment  10  of the first embodiment, however as is seen in  FIG. 3   b  the elastic film  118   b  is cut in a slightly different configuration. The elastic film  118   b  is attached to the side panel nonwoven material  116   b . The configuration of the elastic film  118   a  (not shown) attached to the opposite side panel  116   a  is a mirror image of the elastic film  118   b  shown in  FIG. 3   b . In this configuration the elastic film  118   a  and  118   b  would not extend to the leg hole of the undergarment  110 . This allows the undergarment  110  to be manufactured using leg hole elastic in addition to the elastic film  118   a  and  118   b . In this embodiment the additional step of adhesively applying leg hole elastic is added to the method described above relating to the first embodiment.  
         [0032]     A third embodiment of an undergarment  210  exemplifying the present invention is shown in  FIG. 4   a . This embodiment of the undergarment  210  does not utilize additional waistband elastic. The shape of the elastic film  218   b  which is attached to the side is shown in  FIG. 4   b . The elastic film  218   a  which is attached to side panel  216   a  is a mirror image of the elastic film  218   b  shown in  FIG. 4   b . As is seen in  FIG. 4   b , the elastic film  218   b  is not completely cut through its center. This results in the waistband being elasticized around the entire waist opening when the undergarment  210  is folded and sealed. The undergarment  210  of  FIG. 4   a  is made in substantially the same process as described above referring to the first embodiment. However, the step of applying waistband elastic is omitted. This step can be omitted because the configuration of the elastic film  218   a  and  218   b  is different.  
         [0033]     The foregoing is considered as illustrative only of the principles of the invention. Furthermore, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.