Nonwoven fabrics comprising polylactic acid having improved strength and toughness

Abstract

Nonwoven fabrics having a plurality of fibers that are bonded to each other to form a coherent web, wherein the fibers comprise a blend of a polylactic acid (PLA) and at least one secondary alkane sulfonate are provided. The nonwoven fabrics exhibit increased tensile strengths, elongation and toughness.

That which is claimed: 
     
         1 . A nonwoven fabric comprising a plurality of fibers that are bonded to each other to form a coherent web, wherein the fibers comprise a polymeric blend of a biobased aliphatic polyester and a secondary alkane sulfonate, wherein the amount of secondary alkane sulfonate in the polymeric blend is from about 0.0125 to 2.5 weight percent, based on the total weight of the blend, and wherein the nonwoven fabric exhibits a machine direction Index of Toughness that is from about 2,000 to 7,500 N-%. 
     
     
         2 . The nonwoven fabric according to  claim 1 , the fabric exhibits an increase in cross direction Index of Toughness that is from about 50 to 1,000% in comparison to an identical fabric that does not include the secondary alkane sulfonate. 
     
     
         3 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits an increase in cross direction Index of Toughness that is at least 85% in comparison to an identical fabric that does not include the secondary alkane sulfonate. 
     
     
         4 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits an increase in machine direction Relative Index of Toughness that is from about 100 to 1,000% in comparison to an identical fabric that does not include the secondary alkane sulfonate. 
     
     
         5 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits an increase in machine direction Relative Index of Toughness that is from 80 to 500% in comparison to an identical fabric that does not include the secondary alkane sulfonate. 
     
     
         6 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits a root mean square of the Toughness Index per basis weight is a value that is greater than 65 N-%/g/m 2 , such as a value from about from about 65 to 150 N-%/g/m 2 . 
     
     
         7 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits a machine direction Index of Toughness that is from about 2,300 to 6,000 N-%. 
     
     
         8 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits a cross direction Index of Toughness that is from about 1,000 to 5,000 N-%. 
     
     
         9 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits a cross direction Index of Toughness that is from about 1,250 to 5,000 N-%. 
     
     
         10 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits a cross direction Index of Toughness that is from about 1,250 to 3,500 N-%. 
     
     
         11 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits an increase in tensile strength in at least one of the machine direction or cross direction that is from 50% to 200% in comparison to an identical fabric that does not include the secondary alkane sulfonate. 
     
     
         12 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits an increase in machine direction tensile strength that is from about 50 to 150% in comparison to an identical fabric that does not include the secondary alkane sulfonate. 
     
     
         13 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits an increase in machine direction tensile strength that is from about 55 to 125% in comparison to an identical fabric that does not include the secondary alkane sulfonate. 
     
     
         14 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits an increase in cross direction tensile strength that is from about 50 to 200% in comparison to an identical fabric that does not include the at least one secondary alkane sulfonate. 
     
     
         15 . The nonwoven fabric according to  claim 1 , wherein the fabric exhibits an increase in cross direction tensile strength that is from about 85 to 150% in comparison to an identical fabric that does not include the at least one secondary alkane sulfonate. 
     
     
         16 . The nonwoven fabric according to  claim 1 , wherein the polymeric blend is hydrophilic. 
     
     
         17 . The nonwoven fabric according to  claim 1 , wherein the polymeric blend is hydrophobic. 
     
     
         18 . The fabric of  claim 1 , wherein the plurality of fibers are bonded via calender bonding or air through bonding. 
     
     
         19 . An absorbent article comprising the fabric of  claim 1 . 
     
     
         20 . A spunbond nonwoven fabric comprising a polarity of filaments comprised of a bio-based polymer and wherein the filaments are air through bonded. 
     
     
         21 . A process for preparing a nonwoven fabric, the process comprising:
 blending a biobased aliphatic polyester and a secondary alkane sulfonate, under heat and pressure, to form a stream of molten or semi-molten resin comprised of a blend of the biobased aliphatic polyester and the secondary alkane sulfonate;   forming a plurality of filaments from said stream;   depositing the plurality of filaments onto a collection surface;   exposing the deposited plurality of filaments to ions provided by a first ionization source;   and   bonding the plurality of filaments to form the nonwoven fabric.   
     
     
         22 . The process of  claim 21 , wherein the amount of secondary alkane sulfonate in the blend is from about 0.0125 to 2.5 weight percent, based on the total weight of the blend.