Method of easy production of nonwoven fabric having at least one projection and at least one recess, and method of easy processing of nonwoven fabric
It is an object of the invention to provide a method of easy production of a nonwoven fabric having at least one projection and at least one recess and to a method of easy processing of a nonwoven fabric. A method of producing a nonwoven fabric having at least one projection and at least one recess, comprising the steps of non-homogeneous stretching a nonwoven fabric so as to form a nonwoven fabric with high-stretch regions and low-stretch regions, and forming a nonwoven fabric having at least one projection and at least one recess by placing the nonwoven fabric with high-stretch regions and low-stretch regions on a support and spraying a fluid onto the nonwoven fabric with high-stretch regions and low-stretch regions for treatment.
1. A method of producing a nonwoven fabric having at least one projection and at least one recess, the method comprising:
non-homogeneous stretching a nonwoven fabric so as to form high-stretch regions and low-stretch regions in the nonwoven fabric, and
forming at least one projection and at least one recess by
placing the nonwoven fabric with the high-stretch regions and the low-stretch regions on a fluid-permeable support, and
spraying a fluid from a fluid nozzle onto the nonwoven fabric with the high-stretch regions and the low-stretch regions for treatment,
wherein
the fluid-permeable support has protrusions and depressions with predetermined shapes in contact with the nonwoven fabric which has the high-stretch regions and the low-stretch regions, and
a fluid permeability of the protrusions is lower than a fluid permeability of the depressions.
2. The method according to claim 1 , wherein the non-homogeneous stretching is carried out by
passing the nonwoven fabric in a machine direction through a gap between a pair of gear rolls with rotational axes that are perpendicular to the machine direction, and
rotating the gear rolls while a plurality of teeth situated on peripheral surfaces of the gear rolls are mutually engaged.
3. The method according to claim 2 , wherein
the plurality of teeth is situated around the peripheral surfaces and along the rotational axes, and
the high-stretch regions and low-stretch regions are formed to be parallel to the machine direction, and alternately arranged in a cross direction which is perpendicular to the machine direction.
4. The method according to claim 1 , wherein the support is a conveyor net, a paper-making web or a punching plate.
5. The method according to claim 1 , wherein the protrusions and depressions are parallel to a cross direction which is perpendicular to a machine direction, in which the nonwoven fabric has been non-homogeneously stretched, and are situated in an alternating fashion in the machine direction.
6. The method according to claim 1 , wherein the fluid is selected from the group consisting of air, water vapor and water.
7. The method according to claim 1 , wherein the nonwoven fabric is selected from the group consisting of air-through nonwoven fabrics, spunbond nonwoven fabrics, point bond nonwoven fabrics and elastic nonwoven fabrics.
8. The method according to claim 1 , wherein the nonwoven fabric having the at least one projection and the at least one recess has air permeability in the thickness direction that is at least 3 times the air permeability in the thickness direction of the nonwoven fabric before being subjected to the non-homogeneous stretching.
9. The method according to claim 1 , wherein the nonwoven fabric having the at least one projection and the at least one recess has air permeability in the planar direction of at least 5 m 3 /m 2 /min.
10. The method according to claim 1 , wherein the nonwoven fabric having the at least one projection and the at least one recess has a maximum point elongation of 80% or greater in a cross direction which is perpendicular to a machine direction in which the nonwoven fabric has been non-homogeneously stretched.
11. The method according to claim 1 , wherein
the protrusions and depressions with the predetermined shapes are in contact with a first side of the nonwoven fabric which has the high-stretch regions and the low-stretch regions, and
the fluid is sprayed from the fluid nozzle onto a second side of the nonwoven fabric placed on the fluid-permeable support, the second side opposite to the first side in a thickness direction of the nonwoven fabric.
12. A method of processing a nonwoven fabric, said method comprising:
non-homogeneous stretching a nonwoven fabric so as to form high-stretch regions and low-stretch regions in the nonwoven fabric, and
forming at least one projection and at least one recess by
placing the nonwoven fabric with the high-stretch regions and the low-stretch regions on a fluid-permeable support, and
spraying a fluid from a fluid nozzle onto the nonwoven fabric with the high-stretch regions and the low-stretch regions for treatment,
wherein
the fluid-permeable support has protrusions and depressions with predetermined shapes in contact with the nonwoven fabric which has the high-stretch regions and the low-stretch regions, and
a fluid permeability of the protrusions is lower than a fluid permeability of the depressions.