Patterned Nonwoven Substrates Made from Forming Surface with Regions of High Porosity and Low Porosity

Abstract

A process and system for producing nonwoven substrates are disclosed. Also disclosed is a forming surface or forming wire for producing the substrates. The forming surface includes a pattern of high porosity zones and low porosity zones. The low porosity zones have a non-zero but low porosity. A wet suspension of fibers is deposited onto the forming surface to form nonwoven substrates having areas of high basis weight and low basis weight. The low porosity zones have a width dimension that is greater than the average fiber length of at least some of the types of fibers contained in the fiber furnish to form substrates having exceptional properties, especially with respect to fluid control properties.

1 . A process for forming nonwoven substrates comprising:
 depositing a wet suspension of fibers onto a forming surface, the suspension of fibers including at least a first type of fiber having an average fiber length, the forming surface including a pattern of porous first zones and porous second zones, the first zones having a porosity greater than a porosity of the second zones, the porosity of the second zones being at least 50% less than the porosity of the first zones, wherein the suspension of fibers contains a plurality of different types of fibers and the second zones have a width dimension that is greater in distance than the average fiber length of the fiber type with the longest fibers in the suspension of fibers; and   draining fluids from the forming surface causing a nonwoven substrate to form having high basis weight areas corresponding to the first zones and low basis weight areas corresponding to the second zones.   
     
     
         2 . A process as defined in  claim 1 , wherein the porosity of the second zones is at least 80% less. 
     
     
         3 . A process as defined in  claim 1  wherein the second zones have a porosity such that the second zones have from about 0.5% to about 20% open area. 
     
     
         4 . (canceled) 
     
     
         5 . A process as defined in  claim 1 , wherein the suspension of fibers contains superabsorbent particles. 
     
     
         6 . A process as defined in  claim 1 , wherein the width dimension of the second zones is greater than about 4 mm. 
     
     
         7 . A process as defined in  claim 1 , wherein the second zones form columns on the forming surface, wherein the columns are linear and parallel, wherein the columns have a width dimension of from about 4 mm to about 10 mm and the columns are spaced apart a distance of from about 6 mm to about 20 mm. 
     
     
         8 . (canceled) 
     
     
         9 . (canceled) 
     
     
         10 . A process as defined in  claim 1 , wherein the nonwoven substrate is wound into a roll. 
     
     
         11 . A process as defined in  any of the preceding claim 1 , further comprising the step of slitting the nonwoven substrate along the second zones. 
     
     
         12 . A process as defined in  claim 1 , wherein the low basis weight areas have a basis weight that is greater than about 50%. 
     
     
         13 . A process as defined in  claim 1 , wherein the low basis weight areas have a thickness that is greater than about 50%. 
     
     
         14 . A process as defined in  claim 1 , wherein the forming surface is planar and does not include raised areas on a top surface. 
     
     
         15 . A process as defined in  claim 1 , wherein the forming surface comprises a fabric formed from woven yarns, the second zones comprising zones where an additive material has been applied to the fabric. 
     
     
         16 . A process as defined in  claim 1 , wherein the wet suspension of fibers comprises a blend of synthetic polymer fibers, pulp fibers, superabsorbent particles, or mixtures thereof. 
     
     
         17 . A process as defined in  claim 1 , wherein the wet suspension of fibers comprises polymer synthetic fibers. 
     
     
         18 . A process as defined in  claim 1 , wherein the wet suspension of fibers comprises a foamed suspension of fibers to produce a foam formed substrate. 
     
     
         19 . A process as defined in  claim 18 , wherein the foamed suspension of fibers is formed by combining a foam with a fiber furnish, the foam having a density of from about 200 g/L to about 600 g/L. 
     
     
         20 . A process as defined in  claim 18 , wherein the foamed suspension is formed by combining a foaming agent with water, the foamed suspension of fibers containing from about 40% to about 80% by volume air. 
     
     
         21 . A process as defined in  claim 1 , wherein the dried nonwoven substrate has an average basis weight of from about 20 gsm to about 800 gsm. 
     
     
         22 . A process as defined in  claim 1 , wherein the nonwoven substrate is continuous. 
     
     
         23 . A nonwoven material as defined in  claim 1 , wherein the nonwoven material contains pulp fibers. 
     
     
         24 . A forming sheet for producing nonwoven substrates comprising:
 a forming wire comprising a fabric formed from woven yarns, the fabric including a top, forming surface that is planar and does not include raised areas, the top, forming surface including a pattern of porous first zones and porous second zones, the first zones having a porosity greater than a porosity of the second zones, the porosity of the second zones being at least 50% less than the porosity of the first zones, the second zones having a width dimension that is greater than about 4 mm.   
     
     
         25 . (canceled) 
     
     
         26 . A forming sheet as defined in  claim 24 , wherein the second zones comprise parallel columns, wherein the columns have a wavy shape. 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . A nonwoven substrate comprising:
 a continuous, nonwoven web having a first surface and a second and opposite surface, the nonwoven web comprising synthetic polymer fibers;   the nonwoven web having an average basis weight of from about 30 gsm to about 800 gsm;   and wherein the nonwoven web includes a pattern of high basis weight areas and low basis weight areas, wherein the low basis weight areas have a basis weight that is at least about 50% less than a basis weight of the high basis weight areas, wherein the low basis weight areas have a width dimension that is greater in distance than the average fiber length of the fiber type with the longest fibers in the suspension of fibers. A nonwoven substrate as defined in claim  29 ,   wherein the nonwoven substrate further contains binder fibers.   
     
     
         30 . (canceled) 
     
     
         31 . A nonwoven substrate as defined in  claim 29 , wherein the nonwoven substrate further contains a superabsorbent material, the superabsorbent material being present in the nonwoven substrate in an amount from about 10% by weight to about 90% by weight, wherein the nonwoven substrate includes a top layer, a middle layer, and a bottom layer, and wherein all of the superabsorbent material is contained in the middle layer. 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . (canceled) 
     
     
         35 . (canceled) 
     
     
         36 . (canceled) 
     
     
         37 . (canceled) 
     
     
         38 . (canceled) 
     
     
         39 . (canceled)