Nonwoven fabric

Abstract

A nonwoven fabric provided with concave/convex portions, and openings, which can be adjusted to densify only a part of the peripheral edges of the openings, without excessively increasing the fiber density in the convex portions and the concave portions. A fiber web can be moved to an area where the down-slanting wires of woven wire extending in the direction of width (WD), thereby forming a first side edge portion in the openings. The fiber web is hardly displaced to the opposite side edges of the first side edges, namely a second side edge portions.

1 . A nonwoven fabric comprising:
 a plurality of openings formed along a first direction;   a first side edge portion allocated as one area in the vicinity of a side edge portion of the opening when viewed from a second direction orthogonal to the first direction; and   a second side edge portion allocated as the other area in the vicinity of the side edge portion of the opening, separated from a net-shaped side edge portion by the opening,   the first side edge portion having a higher fiber density than the second side edge portion.   
     
     
         2 . The nonwoven fabric according to  claim 1 , wherein the first side edge portion has a higher basis weight than the second side edge portion. 
     
     
         3 . The nonwoven fabric according to  claim 1 , further comprising:
 a first opening and a second opening adjacent to each other in an arrangement of the plurality of openings; and   a first connecting part of a fiber between the first opening and the second opening,   the first connecting part having a higher fiber density than the second side edge portion in the first openings.   
     
     
         4 . The nonwoven fabric according to  claim 3 , wherein at the first side edge portion in the second opening, a content ratio of fibers oriented in the first direction is higher than a content ratio of fibers oriented in the second direction. 
     
     
         5 . The nonwoven fabric according to  claim 3 , wherein at the first connecting part, the content ratio of fibers oriented in the second direction is higher than the content ratio of fibers oriented in the first direction. 
     
     
         6 . The nonwoven fabric according to  claim 3 , wherein the first connecting part has a higher basis weight than the second side edge portion in the first opening. 
     
     
         7 . The nonwoven fabric according to  claim 3 , further comprising:
 a third opening adjacent to the first opening on the opposite side of the second opening in the arrangement of the plurality of openings; and   a second connecting part of fibers between the first opening and the third opening,   the second connecting part having a higher fiber density than the second side edge portion in the first opening.   
     
     
         8 . The nonwoven fabric according to  claim 7 , wherein the first side edge portion in the second opening and the first side edge portion in the first opening are located on opposite sides in the second direction,
 the first side edge portion in the third opening and the first side edge portion in the first opening are located on opposite sides in the second direction, and   the first side edge portion in the second opening, which is an area having a higher fiber density than the second side edge portion, the first connecting part, the first side edge portion in the first opening, the second connecting part, and the first side edge portion in the third opening are continued in a meandering shape.   
     
     
         9 . The nonwoven fabric according to  claim 7 , wherein the first connecting part has a fiber density of at least 0.05 g/cm 3 , having at least 1.1 times a fiber density of the second side edge portion in at least one of either of the first opening and the second opening, and
 the second connecting part has a fiber density of at least 0.05 g/cm 3 , having at least 1.1 times a fiber density of the second side edge portion in at least one of either of the first opening and the second opening.   
     
     
         10 . The nonwoven fabric according to  claim 7 , wherein at the first side edge portion in the third opening, a content ratio of fibers oriented in the first direction is higher than a content ratio of fibers oriented in the second direction. 
     
     
         11 . The nonwoven fabric according to  claim 7 , wherein at the second connecting part, a content ratio of fibers oriented in the second direction is higher than a content ratio of fibers oriented in the first direction. 
     
     
         12 . The nonwoven fabric according to  claim 7 , wherein the second connecting part has a higher basis weight than the second side edge portion in the first opening. 
     
     
         13 . The nonwoven fabric according to  claim 7 , wherein a basis weight of the first side edge portion in the first opening, a basis weight of the first side edge portion in the second opening, and a basis weight of the first side edge portion in the third opening are 15 to 250 g/cm 3 , respectively, each being at least 1.1 times a basis weight of the second side edge portion in the first opening, a basis weight of the second side edge portion in the second opening, and a basis weight of the second side edge portion in the third opening, respectively. 
     
     
         14 . The nonwoven fabric according to  claim 1 , further comprising:
 a plurality of groove portions formed on one surface of the nonwoven fabric, so as to extend in the first direction; and   a plurality of raised ridge portions formed so as to extend in the first direction on one surface, the raised ridge portions being adjacent to the plurality of groove portions, respectively,   the plurality of openings being formed along the plurality of grooves, respectively.   
     
     
         15 . The nonwoven fabric according to  claim 1 , wherein the shape of each of the plurality of openings is selected from a substantially circular shape and a substantially elliptical shape. 
     
     
         16 . A nonwoven fabric including an area of density change in which the fiber density continuously or intermittently changes, the area of density change having a plurality of high-density areas extending in a predetermined first direction identical with a process flow direction in a machine when manufacturing the nonwoven fabric. 
     
     
         17 . The nonwoven fabric according to  claim 16 , wherein the high-density areas include a plurality of C-shaped high-density areas, and one side of the area of high-density has a low fiber density, when viewed from a second direction orthogonal to the first direction, respectively. 
     
     
         18 . The nonwoven fabric according to  claim 16 , wherein the high-density areas include a meandering shaped area of high-density extending in a meandering shape in the first direction.