Patent ID: 8720021

Claim:
A method of increasing a thickness of a non-woven fabric, said method comprising: feeding a web of non-woven fabric in a machine direction, wherein said non-woven fabric includes a mess of thermoplastic synthetic fibers entangled one with another, has transverse direction, a longitudinal direction and a thickness direction being orthogonal one to another, and upper and lower surfaces opposite to each other in said thickness direction, and extends in said transverse direction as well as in said longitudinal direction; and applying first jet streams of hot gas in said thickness direction to said web of non-woven fabric while said web is being in said machine direction to increase said thickness of said non-woven fabric, wherein a temperature of said first jet streams of hot gas is lower than a temperature at which thermoplastics forming a surface of said thermoplastic synthetic fibers begin to melt; and said applying said first jet streams of hot gas farther comprises: heating said non-woven fabric by applying said first jet streams of gas on one surface of said upper and lower surfaces of said non-woven fabric in a single direction so that said first jet streams of hot gas penetrate fiber interstices formed of said mass of thermoplastic synthetic fibers; and striking said first jet streams of hot gas against a stream diverting member, said stream diverting member being in direct contact with the non-woven fabric so that pathways of said first jet streams of hot gas are diverted by the stream diverting member so as to cause said first jet stream of hot gas to heat said non-woven fabric further and thereby to increase said thickness of said non-woven fabric.