Durably hydrophilic carded nonwovens

Abstract

A carded nonwoven (110) including synthetic staple fibers (120), wherein the synthetic staple fibers have a hydrophilic polypropylene-based composition, said hydrophilic polypropylene-based composition having a polypropylene-based matrix, an ethylene-propylene copolymer additive and a hydrophilic melt additive is disclosed.

What is claimed is: 
     
         1 . A carded nonwoven comprising synthetic staple fibers, wherein the synthetic staple fibers comprise or consist of a hydrophilic polypropylene-based composition, said hydrophilic polypropylene-based composition comprising a polypropylene-based matrix, an ethylene-propylene copolymer additive and a hydrophilic melt additive. 
     
     
         2 . The carded nonwoven according to  claim 1 , wherein the polypropylene-based matrix is a propylene homopolymer (h-PP), a propylene co-polymer (CoPP) or a mixture thereof. 
     
     
         3 . The carded nonwoven according to  claim 1 , wherein the synthetic staple fibers are selected from a) mono-component fibers consisting of the hydrophilic polypropylene-based composition, or b) bi-component fibers comprising a sheath/core structure wherein the sheath consists of the hydrophilic polypropylene-based composition, or a mixture of a) and b). 
     
     
         4 . The carded nonwoven according to  claim 1 , wherein the ethylene-propylene copolymer additive is metallocene catalyzed and has a peak molecular weight between about 100,000 g/mol and about 800,000 g/mol, wherein the peak molecular weight is measured by the Peak Molecular Weight Measurement Method indicated herein. 
     
     
         5 . The carded nonwoven according to  claim 1 , wherein the hydrophilic melt additive comprises or consists of one or more ethoxylated surfactants. 
     
     
         6 . The carded nonwoven according to  claim 5 , wherein the one or more ethoxylated surfactants have the formula: 
       
         
           
           
               
               
           
         
         with x ranging from about 2 to about 100 and y ranging from about 10 to about 24. 
       
     
     
         7 . The carded nonwoven according to  claim 1 , wherein the hydrophilic melt additive comprises a first wetting agent and a second wetting agent, wherein the first wetting agent is at least one water-insoluble, nonionic alkoxylated alkyl phenol, and wherein the second wetting agent is at least one compound selected from the group consisting of an alkoxylated fatty alcohol and a water-soluble, nonionic, non-hydrolyzable polyoxyalkylene-modified organosilicone polymer. 
     
     
         8 . The carded nonwoven according to  claim 1 , wherein the hydrophilic polypropylene-based composition comprises by weight of the hydrophilic polypropylene-based composition:
 at least about 50% of the polypropylene-based matrix;   from about 5% to about 25% of the ethylene-propylene copolymer additive.   
     
     
         9 . The carded nonwoven according to  claim 8 , wherein the hydrophilic polypropylene-based composition comprises by weight of the hydrophilic polypropylene-based composition:
 at least about 65%, of the polypropylene-based matrix;   from about 10% to about 20%, of the ethylene-propylene copolymer additive.   
     
     
         10 . The carded nonwoven according to  claim 1 , wherein the carded nonwoven is selected from the group consisting of:
 a carded calendared nonwoven,   an air-through bonded carded nonwoven,   a resin bonded carded nonwoven, and   a needle-punched carded nonwoven.   
     
     
         11 . The carded nonwoven according to  claim 1 , wherein the carded nonwoven has a basis weight in the range of from about 10 g/m 2  to about 40 g/m 2 . 
     
     
         12 . The carded nonwoven according to  any of the preceding claims , wherein the carded nonwoven is an air-through bonded carded nonwoven comprising a mixture of:
 bi-component fibers with PE sheath; and   bi-component fibers with CoPP sheath;   wherein the CoPP sheath consists of the hydrophilic polypropylene-based composition.   
     
     
         13 . The carded nonwoven according to  claim 1 , wherein the carded nonwoven is a resin bonded carded nonwoven comprising a mix of PET fibers and PP fibers, wherein the PP fibers comprise the hydrophilic polypropylene-based composition. 
     
     
         14 . The carded nonwoven according to  claim 1 , wherein the carded nonwoven is a resin bonded carded nonwoven comprising PET fibers and PET/PP bicomponent fibers, wherein the PP sheath of the bicomponent fibers consists of the hydrophilic polypropylene-based composition. 
     
     
         15 . The carded nonwoven according to  claim 1 , wherein the polypropylene-based matrix has a Melting Peak Temperature (Tmp) in the range of from about 130° C. to about 180° C. and the ethylene-propylene copolymer additive has a Melting Peak Temperature (Tmp) in the range of from about 40° C. to about 100° C., wherein the Melting Peak Temperature is measured by the Melting Peak Temperature Test Method. 
     
     
         16 . The carded nonwoven according to  claim 1 , wherein the carded nonwoven has a Sink Time of less than 10 min at the Second Cycle, as measured according to Sink Time Method. 
     
     
         17 . The carded nonwoven according to  claim 16 , wherein the carded nonwoven has a Sink Time of less than less than 30 s. 
     
     
         18 . The carded nonwoven according to  claim 1 , wherein the enthalpy of crystallization of the ethylene-propylene copolymer additive is in the range of from about 0.5 J/g to about 40 J/g, and the polypropylene-based matrix has an enthalpy of crystallization exceeding 40 J/g, as measured by the Enthalpy of Crystallization Test Method. 
     
     
         19 . The carded nonwoven according to  claim 18 , wherein the enthalpy of crystallization of the ethylene-propylene copolymer additive is in the range of from about 0.5 J/g to about 35 J/g, and the polypropylene-based matrix has an enthalpy of crystallization of at least 45 J/g. 
     
     
         20 . Synthetic staple fibers comprising or consisting of a hydrophilic polypropylene-based composition, said hydrophilic polypropylene-based composition comprising a polypropylene-based matrix, an ethylene-propylene copolymer additive and a hydrophilic melt additive.