Spunbonded non-woven fabric and method for manufacturing same

Abstract

A nonwoven fabric formed of an olefin-based resin composition (I) containing an olefin-based polymer (i) satisfying specific requirements; a spunbond nonwoven fabric obtained by melt-extruding and molding the olefin-based resin composition (I) at a resin temperature of 220° C. or lower, and a method for producing it; a multilayer nonwoven fabric containing the spunbond nonwoven fabric; a nonwoven fabric and a multilayer nonwoven fabric including composite fibers containing an olefin-based resin composition (II) containing an olefin-based polymer (ii) satisfying specific requirements; and a fiber product using the spunbond nonwoven fabric, the nonwoven fabric of composite fibers, or the multilayer nonwoven fabric.

1 : A nonwoven fabric formed of composite fibers comprising the following first component and second component:
 first component: an olefin-based resin composition (I) containing an olefin-based polymer (i) satisfying the following requirements (a) and (b):   (a) the melt flow rate (MFR) of the olefin-based polymer (i), as measured under the condition of a temperature of 23° C. and a load of 21.18 N, is 1,000 g/10 min or more; and   (b) the melting endothermic amount ΔH−D, as measured from the melting endothermic curve drawn by keeping the olefin-based polymer (i) at −10° C. in a nitrogen atmosphere for 5 minutes and then heating it at 10° C./min in a nitrogen atmosphere using a differential scanning calorimeter (DSC), is less than 80 J/g, and   second component: an olefin -based resin composition (II) containing an olefin-based polymer (ii) satisfying the following requirements (e) and (f):   (e) the melt flow rate (MRF) of the olefin-based polymer (ii), as measured under the condition of a temperature of 230° C. and a load of 21.18 N, is 1 g/10 mm or more and 100 g/10 min or less; and   (f) the melting point (Tm−D) of the olefin-based polymer (b), as defined as a peak top of a peak observed on the highest temperature side of the melting endothermic curve drawn by keeping the composition at −10° C. in a nitrogen atmosphere for 5 minutes and then heating it at 10° C./min in a nitrogen atmosphere using a differential scanning calorimeter (DSC), is higher than 120° C.   
     
     
         2 : The nonwoven fabric formed of composite fibers according to  claim 1 , wherein the content of the olefin-based polymer (i) in the olefin-based resin composition (I) is 1 to 50% by mass relative to the total amount, 100% by mass of the olefin-based resin composition (I). 
     
     
         3 : The nonwoven fabric formed of composite fibers according to  claim 1 , wherein the composite fibers are at least one kind selected from the group consisting of a core-sheath type fiber, a side-by-side type fiber and an eccentric core-sheath type fiber. 
     
     
         4 : The nonwoven fabric formed of composite fibers according to  claim 1 , wherein the olefin-based polymer (i) is a propylene based polymer. 
     
     
         5 : A multilayer nonwoven fabric comprising two or more nonwoven fabric layers, wherein at least one nonwoven fabric layer of the multilayer nonwoven fabric is the nonwoven fabric formed of composite fibers according to  claim 1 . 
     
     
         6 : The multilayer nonwoven fabric according to  claim 5 , wherein at least one nonwoven fabric layer of the multilayer nonwoven fabric is a melt-blown nonwoven fabric. 
     
     
         7 : A nonwoven fabric formed of composite fibers comprising the following first component and second component:
 first component: an olefin-based resin composition (I) containing an olefin-based polymer (i) satisfying the following requirements (a) and (b):   (a) the melt flow rate (MFR) of the olefin-based polymer (i), as measured under the condition of a temperature of 230° C. and a load of 21.18 N, is 1,000 g/1.0 min or more; and   (b) the melting endothermic amount ΔH−D, as measured from the melting endothermic curve drawn by keeping the olefin-based polymer (i) at −10° C. in a nitrogen atmosphere for 5 minutes and then heating it at 10° C./min in a nitrogen atmosphere using a differential scanning calorimeter (DSC), is less than 80 J/g, and   second component: an olefin-based resin composition (II) containing an olefin based polymer (ii) satisfying the following requirements (e) and (f):   (e) the melt flow rate (MFR) of the olefin-based polymer (ii), as measured under the condition of a temperature of 230° C. and a load of 21.18 N, is 1 g/10 min or more and 100 g/10 min or less; and   (f) the melting point (Tm−D) of the olefin-based polymer (ii), as defined as a peak top of a peak observed on the highest temperature side of the melting endothermic curve drawn by keeping the composition at −10° C. in a nitrogen atmosphere for 5 minutes and then heating it at 10° C./min in a nitrogen atmosphere using a differential scanning calorimeter (DSC), is higher than 120° C.,   wherein at least one of the first component and the second component comprises an internal release agent.   
     
     
         8 : The nonwoven fabric formed of composite fibers according to  claim 7 , wherein a content of the internal release agent is 1.0 to 10,000 ppm by mass based on the composition of the first component or the second component comprising the internal release agent. 
     
     
         9 : A nonwoven fabric formed of composite fibers comprising the following first component and second component:
 first component: an olefin-based resin composition (I) containing an olefin-based polymer (i) satisfying the following requirements (a) and (b):   (a) the melt flow rate (MFR) of the olefin-based polymer (i), as measured under the condition of a temperature of 230° C. and a load of 21.18 N, is 1,000 g/10 min or more; and   
       (b) the melting endothermic amount ΔH−D, as measured from the melting endothermic curve drawn by keeping the olefin-based polymer (i) at −10° C. in a nitrogen atmosphere for minutes and then. heating it at 10° C./min in a nitrogen atmosphere using a differential scanning calorimeter (DSC), is less than 80 J/g, and
 second component: an olefin-based resin composition (II) containing an olefin-based polymer (ii) satisfying the following requirements (e) and (f): 
 (e) the melt flow rate (MFR) of the olefin-based polymer (ii), as measured under the condition of a temperature of 230° C. and a load of 21.18 N, is 1 g/10 min or more and 100 g/10 min or less; and 
 (f) the melting point (Tm−D) of the olefin based polymer (ii), as defined as a peak top of a peak observed on the highest temperature side of the melting endothermic curve drawn by keeping the composition at −10° C. in a nitrogen atmosphere for 5 minutes and then heating it at 10° C./min in a nitrogen atmosphere using a differential scanning calorimeter (DSC), is higher than 120° C., 
 wherein at least one of the first component and the second component comprises erucamide. 
 
     
     
         10 : The nonwoven fabric formed of composite fibers according to  claim 9 , wherein a content of the erucamide is 10 to 10,000 ppm by mass based on the composition of the first component or the second component comprising the erucamide. 
     
     
         11 : A multilayer nonwoven fabric comprising two or more nonwoven fabric layers, wherein at least one nonwoven fabric layer of the multilayer nonwoven fabric is the nonwoven fabric formed of composite fibers according to  claim 7 . 
     
     
         12 : The multilayer nonwoven fabric according to  claim 11 , wherein at least one nonwoven fabric layer of the multilayer nonwoven fabric is a melt-blown nonwoven fabric.