Elastic spunbonded nonwoven and elastic nonwoven fabric comprising the same

Abstract

The elastic spunbonded nonwoven has high elastic recovery properties and includes a plurality of multicomponent filaments. Each multicomponent filament, preferably of the sheath/core type, includes a first polymeric component extending along the length of the filament in at least a first section of the filament, and a second polymeric component extending along the length of the filament in at least a second section of the filament that is distinct from the first section. The first polymeric component comprises an elastic propylene-based olefin copolymer, and the second polymeric component comprises an elastic propylene-based olefin and has a melt flow rate that is higher than the melt flow rate of the first polymeric component. The elastic propylene-based olefin copolymer for the first polymeric component and for the second polymeric component includes propylene and from 10 to 25 weight % of one or more C2 and/or C4 to C10 alpha-olefin co-monomers.

1 . An elastic spunbonded nonwoven comprising a plurality of multi-component filaments, wherein each multi-component filament comprises a first polymeric component extending along the length of the filament in at least a first section of the filament, and a second polymeric component extending along the length of the filament in at least a second section of the filament that is distinct from the first section, wherein the first polymeric component comprises an elastic propylene-based olefin copolymer, and the second polymeric component comprises an elastic propylene-based olefin and has a melt flow rate MFR 2  that is higher than the melt flow rate MFR 1  of the first polymeric component, and wherein the elastic propylene-based olefin copolymer for the first polymeric component and for the second polymeric component comprises propylene and from 10 to 25 weight % of one or more C2 and/or C4 to C10 alpha-olefin co-monomers. 
     
     
         2 . An elastic spunbonded nonwoven according to  claim 1 , wherein each multi-component filament comprises a core and an outer sheath, and wherein the core comprises the first polymeric component, and the sheath comprises the second polymeric component. 
     
     
         3 . An elastic spunbonded nonwoven according to  claim 1 , wherein the ratio MFR 2 /MFR 1  is higher than 1.5. 
     
     
         4 . An elastic spunbonded nonwoven according to  claim 1 , wherein the first polymeric component comprises a blend of at least two elastic propylene-based olefin copolymers of different melt flow rate. 
     
     
         5 . An elastic spunbonded nonwoven according to  claim 1 , wherein the elastic propylene-based olefin copolymer for the first polymeric component and for the second polymeric component is an ethylene propylene copolymer. 
     
     
         6 . An elastic spunbonded nonwoven according to  claim 1 , wherein the elastic propylene-based olefin copolymer for the first polymeric component and for the second polymeric component has a melt flow rate of 0.1 to 2000 g/10 min, most preferably greater than 2 g/10 min and less than 100 g/10 min, as measured by ASTM D-1238 at 230° C. and 2.16 kg. 
     
     
         7 . An elastic spunbonded nonwoven according to  claim 1 , wherein the elastic propylene-based olefin copolymer for the first polymeric component and for the second polymeric component has a molecular weight distribution of less than 5, preferably between 1 and 4. 
     
     
         8 . An elastic spunbonded nonwoven according to  claim 1 , wherein the elastic propylene-based olefin copolymer for the first polymeric component and for the second polymeric component comprises at least 80 wt % of propylene units. 
     
     
         9 . An elastic spunbonded nonwoven according to  claim 1 , wherein the elastic propylene-based olefin copolymer for the first polymeric component and for the second polymeric component is a metallocene-catalysed polymer. 
     
     
         10 . An elastic spunbonded nonwoven according to  claim 1 , wherein at least 50% of the whole surface of each filament is constituted by the second polymeric component. 
     
     
         11 . An elastic spunbonded nonwoven according to  claim 10 , wherein 100% of the whole surface of each filament is constituted by the second polymeric component. 
     
     
         12 . An elastic spunbonded nonwoven according to  claim 1 , having a root mean square (RMS) average recovery of at least 85%, said RMS average recovery being calculated from the formula:
   RMS average recovery=[½( R   CD   2   +R   MD   2 )] 1/2 ,   wherein R MD  and R CD  are recovery values (R) measured on a nonwoven specimen respectively in machine direction and cross direction, after 50% elongation and one pull, and calculated from the formula:
     R =[( Ls−Lr )/( Ls−Lo )]%, 
   wherein Ls represents the stretched length of the specimen; Lr represents the recovered length of the specimen, Lo represents the original length of the specimen.   
     
     
         13 . An elastic spunbonded nonwoven according to  claim 12 , and having a RMS recovery, after two successive 50% pulls, of at least 80%. 
     
     
         14 . An elastic spunbonded nonwoven according to  claim 1 , wherein the amount of the first polymeric component is at least 50 wt % of the total weight of the filament, and the amount of the second polymeric component is less than 50 wt % of the total weight of the filament. 
     
     
         15 . A spunbonded nonwoven according to  claim 14 , wherein the amount of the second polymeric component is less than 40 wt % of the total weight of the filament, and preferably equal or less than 30 wt % of the total weight the filament. 
     
     
         16 . An elastic nonwoven fabric comprising at least one first elastic spunbonded nonwoven layer according to  claim 1  and at least one additional nonwoven layer. 
     
     
         17 . An elastic nonwoven fabric according to  claim 16 , wherein the said at least one additional nonwoven layer is selected from the group:
 a carded nonwoven layer, a meltblown layer, a spunbonded layer, a polyolefin-based nonwoven layer, a polypropylene-based nonwoven layer.   
     
     
         18 . An elastic nonwoven fabric according to  claim 16 , comprising at least two additional carded nonwoven layers and wherein the elastic spunbonded nonwoven layer is sandwiched between the two carded layers. 
     
     
         19 . An elastic nonwoven fabric according to  claim 18 , and comprising an additional meltblown layer interposed between the elastic spunbonded nonwoven layer and one carded nonwoven layer. 
     
     
         20 . An elastic nonwoven fabric according to  claim 16 , wherein the layers are bonded together by one of the following bonding technologies: thermal bonding, water needling, mechanical needling, ultrasonic bonding, air trough bonding and chemical bonding. 
     
     
         21 . An elastic nonwoven fabric according to  claim 16 , wherein the layers are perforated. 
     
     
         22 . An elastic nonwoven fabric according to  claim 16 , and having a CD permanent set after two cycles at 150% elongation less than 50%, and preferably less than 40%. 
     
     
         23 . An elastic nonwoven fabric according to  claim 16 , and having a CD elongation@Peak of at least 150%, and preferably of at least 200%. 
     
     
         24 . An elastic nonwoven fabric according to  claim 16  wherein the layers have been hydroentangled. 
     
     
         25 . A hydroentangled elastic nonwoven fabric according to  claim 24 , wherein the layers are perforated, notably by means of hydro jets.