Absorbent Article with a Slitted Absorbent Core

Abstract

The invention relates to slit absorbent articles and the use of slits in absorbent materials to provide improved liquid intake rate, flexibility and softness compared to the unmodified material. The absorbent material, including superabsorbent materials, are particularly useful as absorbent cores in disposable absorbent articles such as diapers, incontinent products, sanitary napkins and the like.

1 . A method of manufacturing an absorbent core for incorporation into a disposable absorbent article, said method comprising:
 providing an absorbent core by providing an absorbent layer containing superabsorbent material and supported on a substrate; and   slitting said absorbent layer at a plurality of locations to define slits penetrating downward through a surface of a layer of the superabsorbent material.   
     
     
         2 . The method of  claim 1 , wherein said slitting provide slits at one or more locations to improve the flexibility of the absorbent core. 
     
     
         3 . The method of  claim 1 , wherein said providing an absorbent core includes providing a non-woven substrate and distributing superabsorbent particles thereon, whereby the superabsorbent particles are intermixed with microfibrillated cellulose and embedded into pores of the nonwoven substrate. 
     
     
         4 . The method of  claim 1 , wherein said providing an absorbent core includes providing a non-woven substrate and distributing superabsorbent particles thereon. 
     
     
         5 . The method of  claim 4 , wherein the absorbent layer provides an absorbent core having about 61% to about 97% by weight of the superabsorbent material, from about 3% to about 39% by weight of non-absorbent nonwoven resilient fibers, and 0% by weight of absorbent hydrophilic fibers, wherein the superabsorbent material comprises particles and the non-absorbent nonwoven resilient fibers form a low-density layer and a high-density layer. 
     
     
         6 . The method of  claim 1 , further comprising providing a second absorbent layer of a nonwoven substrate and superabsorbent particles supported thereon; and
 positioning the first absorbent layer above said second absorbent layer.   
     
     
         7 . The method of  claim 6 , further comprising slitting the second layer prior to positioning the first layer. 
     
     
         8 . (canceled) 
     
     
         9 . The method of  claim 1 , wherein said slitting defines an absorbent core having a slit level of greater than 0.1 cm-1. 
     
     
         10 . (canceled) 
     
     
         11 . The method of  claim 1 , further comprising:
 folding the absorbent core along at least one region of material discontinuity.   
     
     
         12 . The method of  claim 11 , wherein said at least one material discontinuity is defined by at least one slit. 
     
     
         13 . The method of  claim 11 , further comprising:
 mechanically softening the absorbent core.   
     
     
         14 . The method of  claim 1 , further comprising modifying the absorbent core by folding along at least two parallel lines of material discontinuity, wherein said lines are oriented in a generally longitudinal direction of the core and located about a central region, thereby producing an hourglass shaped absorbent core. 
     
     
         15 . The method of  claim 1 , wherein said slitting provides a plurality of slits aligned generally in a longitudinal direction of the core. 
     
     
         16 . The method of  claim 1 , wherein said slitting provides a plurality of slits of different lengths. 
     
     
         17 . The method of  claim 1 , wherein said slitting provides a plurality of slits of different depths. 
     
     
         18 . The method of  claim 1 , wherein said slitting provides a plurality of slits of different depths, including slits extending through the absorbent core. 
     
     
         19 . The method of  claim 1 , wherein said slitting includes providing a plurality of curved slits. 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . The method of  claim 13 , wherein said mechanically softening occurs prior to said slitting. 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . A method of making a disposable absorbent article having a front waist region, a back waist region spaced longitudinally from the front waist region, a pair of side margins extending longitudinally from the front waist region to the back waist region and a crotch region located between the side margins and between the front and back waist regions, said method comprising:
 providing a fluid impervious back sheet;   forming an absorbent core containing superabsorbent material; and   connecting the absorbent core to said back sheet; and   providing a cover layer over the absorbent core, thereby defining, at least partly, the front waist region, the back waist region spaced longitudinally from the front waist region, and the crotch region located generally centrally between said front and back waist regions and between longitudinally extending side margins; and   wherein said forming the absorbent core includes
 providing a nonwoven substrate, 
 distributing superabsorbent particles on the nonwoven substrate, whereby a layer of superabsorbent material is supported on the nonwoven substrate, and 
 slitting at least a portion of said layer of superabsorbent material to provide slits positioned to generally correspond with the crotch region such that said absorbent core having said slits has greater flexibility relative to said absorbent core without said slits. 
   
     
     
         31 . (canceled) 
     
     
         32 . The method of  claim 30 , wherein said slitting renders said absorbent core said greater flexibility along a direction aligned with a machine direction of the backsheet and cover layer. 
     
     
         33 . The method of  claim 30 , wherein said slitting renders said absorbent core said greater flexibility along a lateral direction substantially offset from a longitudinal direction extending through said front and back waist regions, said lateral direction extending laterally through said side margins. 
     
     
         34 . (canceled) 
     
     
         35 . (canceled) 
     
     
         36 . The method of  claim 30 , wherein said
 slitting the absorbent core provides a plurality of slits, with a greater number of slits per unit area defining a region of greater liquid intake as compared to another region having a fewer number of slits per unit area.   
     
     
         37 . (canceled) 
     
     
         38 . The method of  claim 30 , wherein said forming said absorbent core further includes providing a second nonwoven substrate and distributing superabsorbent particles on the second nonwoven substrate to form a second layer of superabsorbent material, and wherein said connecting the absorbent core includes positioning an absorbent core having said first and second layers of superabsorbent material with said first layer positioned above said second layer. 
     
     
         39 . The method of  claim 30 , wherein said slitting provides a plurality of slits having different angular orientations relative to a machine direction of the backsheet and cover layer. 
     
     
         40 . A method of making an absorbent core for incorporation into a disposable absorbent article having a front waist region, a back waist region, a pair of longitudinally extending side margins extending between said front and back regions, and a crotch region positioned generally centrally between said front and back waist regions and between said side margins, said method comprising:
 providing an absorbent layer containing superabsorbent material including providing a non-woven substrate and distributing superabsorbent particles thereon, whereby the superabsorbent particles are intermixed with microfibrillated cellulose and embedded into pores of the nonwoven substrate; and   slitting said absorbent layer at a plurality of locations corresponding to the crotch region to define slits penetrating downward through a surface of a layer of the superabsorbent particles, thereby increasing the liquid intake and flexibility of the absorbent layer; and   wherein the absorbent layer provides an absorbent core having about 61% to about 97% by weight of the superabsorbent material, from about 3% to about 39% by weight of non-absorbent nonwoven resilient fibers, and 0% by weight of absorbent hydrophilic fibers, wherein the superabsorbent material comprises particles and the non-absorbent nonwoven resilient fibers form a low-density layer and a high-density layer.