Process and apparatus for increasing the isotropy in nonwoven fabrics
AssigneeE. I. Du Pont de Nemours and Company
InventorsJames Marshall Oathout, Phillip O. Staples, Donald Floyd Miller
Life of this patent
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Abstract
A method for changing the position of fibers in a nonwoven web to improve the isotropy of the web by using angled stream of fluid wherein the streams form a substantially coplanar curtain and impinge on the fibers at their leading ends, trailing ends or sides.
Claims14
A method for changing the orientation of fibers in a nonwoven web wherein a portion of the fibers are oriented in substantially the machine direction and a portion of the fibers are oriented in substantially the cross-machine direction comprising the steps of
- providing a plurality of fluid jets offset at an appreciable angle from the perpendicular with respect to the web,
- applying a plurality of fluid streams from the jets onto a surface of the nonwoven web at a pressure sufficient to move the fibers into a different orientation wherein the streams form a substantially coplanar curtain,
- locking the perturbed fibers of the nonwoven web to maintain the different orientation of the fibers.
A method for changing the orientation of fibers in a nonwoven web produced by hydroentangling wherein a portion of the fibers are oriented in substantially the machine direction and a portion of the fibers are oriented in substantially the cross-machine direction comprising the steps of
- (a) providing a first plurality of fluid jets offset at an appreciable angle from the perpendicular with respect to the web,
- (b) applying a plurality of fluid streams from the jets of step (a) onto a surface of the nonwoven web at a pressure sufficient to move the fibers into a different position wherein the streams form a substantially coplanar curtain,
- (c) providing a first plurality of nonangled fluid jets,
- (d) applying a first plurality of fluid streams from the first plurality of nonangled jets onto the nonwoven web of step (b), wherein the streams form a substantially coplanar curtain
- (e) providing a second plurality of fluid jets offset at an appreciable angle from the perpendicular with respect to the web,
- (f) applying a plurality of fluid streams from the jets of step (e) onto the nonwoven web of step (d) at a pressure sufficient to move the fibers into a different position wherein the streams form a substantially coplanar curtain,
- (g) providing a second plurality of nonangled jets,
- (h) applying a plurality of fluid streams from the second plurality of nonangled jets onto the nonwoven web of step (f), wherein the streams form a substantially coplanar curtain.
A jet strip having at least one row of a plurality of closely spaced holes therein angled at least about 5 degrees from the vertical and such that the aggregate of individual fluid streams issuing from each of the holes effectively forms a curtain of fluid.
Dependencies are inferred from the claim text.