Patent ID: 7291239
Filing Date: 2007-11-06
Classification: D04H,Y10T

Abstract:
1. A method for producing a high loft, low density nonwoven web, the nonwoven web having x, y and z dimensions, with the x dimension being a machine direction, the y dimension being a cross machine direction and the z dimension being a loft direction, comprising: a) forming a group of crimpable, substantially continuous, spunbond, bicomponent fibers of A/B morphology in an unheated FDU and depositing the group of fibers onto a forming wire; b) first heating the fibers at a time and a temperature sufficient to induce a relaxation of molecular orientation of at least one component of the fiber wherein at most a small degree of nonfunctional bonding occurs between the fibers; c) after said first heating, cooling the group of fibers below a crystallization temperature and thereby inducing the fibers to crimp; d) minimizing the forces which tend to impede crimping of the fibers when performing steps b) and c) whereby the fibers are allowed to crimp in the z-direction; and e) reheating the group of fibers to cause the fibers to bond to each other to form a stable high loft, low density nonwoven web.