High loft nonwoven fabrics

Abstract

Nonwoven fabrics are provided that include a plurality of crimped bicomponent fibers having a first component comprising a first polymeric material comprising a first polymer or a first polymeric blend and a second component comprising a second polymeric material, in which the second polymeric material comprises a second polymeric blend of (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer, and (iii) at least one compatibilizer comprising or consisting of at least one polypropylene-polyethylene copolymer.

What is claimed is: 
     
         1 . A method of making a nonwoven fabric, comprising:
 (a) forming a first polymeric melt comprising a first polymer or a first polymeric blend;   (b) forming a second polymeric melt including a second polymeric blend of (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer having a melt flow rate (MFR) from about 1 to about 15 g/10 min as determined by ASTM D1238 (190C° /2.16 kg), and (iii) at least one compatibilizer comprising a polypropylene-polyethylene copolymer;   (c) forming a plurality of bicomponent fibers via melt-spinning the first polymeric melt and the second polymeric melt through a bicomponent spinnerette pack;   (d) allowing the plurality of bicomponent fibers to crimp prior to or during laydown on a collection surface or subjecting the plurality of bicomponent fibers to a crimping operation to provide a plurality of crimped bicomponent fibers; and   (e) consolidating the plurality of crimped bicomponent fibers to form the nonwoven fabric.   
     
     
         2 . The method of  claim 1 , wherein the first polymeric melt comprises a polyolefin. 
     
     
         3 . The method of  claim 1 , wherein the first polymeric melt comprises a first polypropylene having a first melt flow rate (MFR) and a second polypropylene having a second MFR; wherein the second MFR is the same as or is larger than the first MFR. 
     
     
         4 . The method of  claim 3 , wherein a first MFR-ratio between the second MFR and the first MFR is from about 1:1 to about 60:1. 
     
     
         5 . The method of  claim 3 , wherein the first polymeric melt comprises from about 70 wt. % to about 99 wt. % of a first polypropylene. 
     
     
         6 . The method of  claim 5 , wherein the first polymeric melt comprises from about 1 wt. % to about 10 wt. % of a second polypropylene. 
     
     
         7 . The method of  claim 1 , wherein the second polymeric blend comprises from about 60 to about 90 wt. % of the at least one polypropylene polymer, from about 5 to about 30 wt. % of the at least one polyethylene polymer, and from about 1 to about 10 wt. % of the at least one polypropylene-polyethylene copolymer. 
     
     
         8 . The method of  claim 7 , wherein the at least one polypropylene polymer is a first polypropylene polymer and has a melt flow rate (MFR) of from about 10 to about 100 g/10 min as determined by ASTM D1238 (230C° /2.16 kg), the at least one polyethylene polymer is a first polyethylene polymer and has a MFR from about 1 to about 10 g/10 min as determined by ASTM D1238 (190C° /2.16 kg), and the at least one polypropylene-polyethylene copolymer is a first polypropylene-polyethylene copolymer and has a MFR of from about 0.5 to about 20 g/10 min as determined by ASTM D1238 (230C° /2.16 kg). 
     
     
         9 . The method of  claim 8 , wherein the first polypropylene-polyethylene copolymer is a first block copolymer. 
     
     
         10 . The method of  claim 9 , wherein the first block copolymer is an EP-iPP diblock polymer. 
     
     
         11 . The method of  claim 9 , wherein the first polypropylene-polyethylene copolymer has an ethylene monomer content from about 5 to about 60% by weight. 
     
     
         12 . The method of  claim 1 , wherein the plurality of crimped bicomponent fibers comprise continuous fibers, staple fibers, or a combination thereof. 
     
     
         13 . The method of  claim 1 , wherein the plurality of crimped bicomponent fibers comprise a side-by-side configuration, a sheath-core configuration, a pie configuration, an islands-in-the-sea configuration, a multi-lobed configuration, or any combinations thereof. 
     
     
         14 . The method of  claim 1 , wherein the first polymeric melt comprises from about 20 wt. % to about 80 wt. % of the plurality of crimped bicomponent fibers, and wherein the second polymeric melt comprises from about 80 wt. % to about 20 wt. % of the plurality of crimped bicomponent fibers. 
     
     
         15 . The method of  claim 1 , wherein the plurality of crimped bicomponent fibers define a first nonwoven layer, and wherein the method further comprises attaching one or more additional nonwoven layers including at least a second nonwoven layer to the first nonwoven layer. 
     
     
         16 . The method of  claim 15 , wherein the one or more additional layers comprises a spunbond layer, a meltblown layer, a carded layer, a hydroentangled layer, a cellulosic layer, or any combination thereof. 
     
     
         17 . The method of  claim 16 , wherein the method further comprises depositing one or more cellulosic layers located directly or indirectly between the first nonwoven layer and the second nonwoven layer, wherein the second nonwoven layer comprises a spunbond layer or a spunbond- meltblown-spunbond layer. 
     
     
         18 . The method of  claim 1 , wherein the nonwoven fabric has a basis weight from about 10grams-per-square-meter (gsm) to about 100 gsm. 
     
     
         19 . The method of  claim 1 , wherein the at least one compatibilizer consists of at least one polypropylene-polyethylene copolymer. 
     
     
         20 . A method of making a nonwoven fabric, comprising:
 (a) forming a first polymeric melt comprising a first polymer or a first polymeric blend;   (b) forming a second polymeric melt including a second polymeric blend of (i) at least one polypropylene polymer, (ii) at least one polyethylene polymer having a melt flow rate (MFR) from about 1 to about 15 g/10 min as determined by ASTM D1238 (190 C° /2.16 kg), and (iii) at least one compatibilizer comprising a polypropylene-polyethylene copolymer;   (c) forming a plurality of bicomponent fibers via melt-spinning the first polymeric melt and the second polymeric melt through a bicomponent spinneret pack;   (d) consolidating the plurality of bicomponent fibers to form an intermediate nonwoven fabric; and   (e) subjecting the plurality of bicomponent fibers of the intermediate nonwoven fabric to a crimping operation to provide the nonwoven fabric.