Hydroentangled elastic nonwoven sheet

Abstract

A method for making an elastic fabric with the steps of providing a hydroentangled precursor fabric having at least 1% by weight of binder fibers, heating the precursor fabric to a temperature above the melting point of the binder fibers and then drawing the precursor fabric in the machine direction at a ratio sufficient to reduce the width by more than 20% and at a strain rate of 10 to 800% per minute to produce an elastic fabric having a cross-directional extensibility of about 100% up to 500% and a 30-95% recovery under a 50% extension.

1 . A method for making an elastic fabric comprising the steps of 
 (a) providing a hydroentangled nonwoven precursor fabric containing predominantly non-elastomeric base fibers and at least 1% by weight of thermoplastic binder fibers that have a lower melting point than the base fibers    (b) heating the precursor fabric to a temperature above the melting point of the binder fibers,    (c) drawing the precursor fabric in the machine direction at a ratio sufficient to reduce the width of the precursor by at least 20% and to achieve a cross-direction elongation of above 100% in the resultant elastic fabric.    (d) cooling the stretched web before releasing the tension to create fixed bond points on binder fibers.    
   
   
       2 . The method of  claim 1 , wherein the processing speed is at least 30 meters per minute and preferably 100-300 meters per minute.  
   
   
       3 . The method of  claim 2 , wherein the processing strain rate is 10-800% per minute.  
   
   
       4 . The method of  claim 1 , wherein the drawing step comprises the use of two sets of S-wrap rolls.  
   
   
       5 . The method of  claim 1 , wherein the heating step comprises heating the precursor fabric to a temperature above the melting point of some base fibers.  
   
   
       6 . An elastic fabric composed of non-elastomeric fibers obtained by applying a draw in the machine direction at an elevated temperature to a precursor to reduce the width of the precursor and extend the length from the precursor by more than 20% and achieve in the elastic fabric an increase of extensibility in cross direction of more than 50% of the precursor.  
   
   
       7 . An elastic nonwoven fabric made from an entangled precursor web containing non-elastomeric base fibers and less than 30% of non-elastic thermoplastic binder fibers that have a lower melting point than the base fibers, wherein the precursor web is drawn in the machine direction at an elevated temperature above the melting point of the binder fibers to reduce the width of the precursor by more than 20% and achieve in the elastic nonwoven fabric a cross-directional extensibility of 100% to 500% with a 30-95% recovery from a 50% elongation.  
   
   
       8 . The elastic fabric of  claim 7 , having a 40-85% recovery under a 100% elongation.  
   
   
       9 . The elastic fabric of  claim 7 , having a 15-75% recovery under a 150% elongation.  
   
   
       10 . The elastic fabric of  claim 7 , comprising at least 1% by weight of binder fibers.  
   
   
       11 . The elastic fabric of  claim 7  in a form selected from the group consisting of apertured fabric, mesh fabric, and net fabric.  
   
   
       12 . The elastic fabric of  claim 7 , comprising thermoplastic base fibers selected from the group consisting of polypropylene, polyethylene, polyester, acrylic, polystyrene polyamide and mixtures of thermoplastic fiber and non-thermoplastic fibers selected from the group consisting of wood pulp, cotton, rayon, and lyocell.  
   
   
       13 . The elastic fabric of  claim 7 , comprising binder fibers selected from the group consisting of polypropylene, polyethylene, polyester, acrylic, polystyrene, polyamide, co-polyester, sheath/core co-polyester/polyester, sheath/core polyethylene/polyester, and sheath/core non-elastic polyolefin/elastomer.  
   
   
       14 . The elastic fabric of  claim 7 , comprising a base fiber blend of thermoplastic and non thermoplastic fibers selected from the group consisting of cotton, wood, and synthetics.  
   
   
       15 . The elastic fabric of  claim 13 , wherein the synthetic is an aramid.  
   
   
       16 . The elastic fabric of  claim 7 , comprising thermoplastic base fibers of polyester and sheath/core binder fibers, wherein the core is polyester.  
   
   
       17 . The elastic fabric of  claim 16 , wherein the sheath is a co-polyester.  
   
   
       18 . The elastic fabric of  claim 16 , wherein the sheath is polyethylene.