Nonwoven fabric
Nonwoven fabric has a plurality of groove portions continuously formed along a predetermined direction, and a plurality of raised ridge portions formed continuously along the groove portions, each adjacent to the groove portions. The basis weight is the least, and the content percentage of laterally-oriented fibers is high, and the content percentage of longitudinally-oriented fibers is low at the groove portions of the nonwoven fabric. Sides at the raised ridge portions are formed so that their basis weight is the greatest, and the content percentage of the fiber oriented toward a longitudinal direction is high.
1. A nonwoven fabric of overlapping fibers bonded in a three-dimensional structure, said non-woven fabric comprising on a first surface thereof:
a plurality of groove portions longitudinally extending in a first direction; and
a plurality of raised ridge portions longitudinally extending in the first direction, said groove portions and raised ridge portions being alternately arranged adjacent to each other in a second direction transverse to the first direction;
wherein
said fabric comprises
first oriented fibers oriented in the first direction; and
second oriented fibers oriented in the second direction;
each of the raised ridge portions has side portions opposite one another in the second direction, and a central portion between said side portions;
the central portion has a height between 0.3 mm and 15 mm in a thickness direction of the fabric, and said height of the central portion is greater than that of said side portions;
the side portions include the first oriented fibers which have been moved from adjacent groove portions to said side portions by a fluid directly blown upon the groove portions during manufacture of the fabric, and the side portions have a content percentage of the first oriented fibers greater than that of the central portion;
a content percentage of the second oriented fibers in the groove portions is greater than those in the side portions and in the central portions;
a content percentage of the first oriented fibers in the groove portions is lower than that in the central portions;
a fiber density at a bottom portion of each of the groove portions is between 0.002 to 0.18 g/cm 3 ;
a fiber density in each of the central portions of the raised ridge portions is between 0.005 to 0.20 g/cm 3 ; and
a fiber density in each of the side portions of the raised ridge portions is between 0.007 to 0.25 g/cm 3 .
2. The nonwoven fabric according to claim 1 , wherein
the content percentage of the first oriented fibers in the central portions is at least 10% lower than that in the side portions and at least 10% higher than that in the groove portions.
3. The nonwoven fabric according to claim 2 , wherein
the content percentage of the first oriented fibers in the central portions is in a range between 40-80%;
the content percentage of the first oriented fibers in the side portions is in a range between 55 to 100%; and
the content percentage of the second oriented fibers in the groove portions is in a range between 55 to 100%.
4. The nonwoven fabric according to claim 1 , wherein
in each of the side portions, the content percentage of the first oriented fibers is greater than that of the second oriented fibers;
in each of the groove portions, the content percentage of the second oriented fibers oriented in the second direction that is perpendicular to the first direction is greater than that of the first oriented fibers oriented in the first direction;
in each of the central portions, the content percentage of the first oriented fibers is greater than that of the second oriented fibers.
5. The nonwoven fabric according to claim 4 , wherein
an average basis weight of entire said nonwoven fabric including the groove portions and the raised ridge portions is between 20 to 100 g/m 2 ;
a basis weight of the bottom portion of each of the groove portions is lower than the average basis weight of the entire nonwoven fabric, and is between 5 to 80 g/m 2 ; and
an average basis weight of each of the raised ridge portions is greater than the basis weight of the bottom portion of each of the groove portions, wherein the basis weight of each of the central portions is between 15 to 250 g/m 2 , and the basis weight of each of the side portions is between 20 to 280 g/m 2 .