Process for laying fibrous webs from a centrifugal spinning process

Patent metadata

Field	Value
Publication number	US-9670595-B2
Application number	US-201214364708-A
Country	US
Kind code	B2
Filing date	Dec 20, 2012
Priority date	Dec 21, 2011
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

A method for laying down a nanoweb of nanofibers from a centrifugal spinning process by a combination of an air flow field and a charging arrangement. Fibrous streams in the form of fibrils of molten polymer or polymer solution are discharged from a rotating member into an air flow field that is essentially parallel to the direction of discharge of fibrils at the point of discharge of the fibrils. The fibrous streams are attenuated and directed by means of the air flow field onto the surface of a collector to form a nanoweb. The fibrous streams are charged along all or at least a portion of their route from the point of discharge to the surface of the collector.

First claim

We claim:

1. A method for laying down a nanoweb from a centrifugal spinning process comprising the steps of:
(i) ejecting a polymer melt in air or an inert gas from a surface of a rotating member comprising a disk or cup rotating about an axis and located in a spinning head, wherein molten fibrils exit the surface in a direction essentially perpendicular to the axis of rotation of the disc or cup and into an electric field established between a fiber collector and the spinning head; and wherein the fibrils are attenuated by the centrifugal force and cool to form nanofibers that have a number average fiber diameter of less than 1,000 nm;
(ii) applying a charge to the polymer melt, the molten fibrils, the nanofibers, or any combination of these three locations;
(iii) directing the nanofibers with a shaping air flow towards a collector that has a charge opposite to the charge on the fibers in (ii) above;
(iv) collecting the polymeric nanofibers on the collector;

wherein turbulent motion of air located between the spinning head and the collector is suppressed by air jets supplied by nozzles located on the underside of the rotating member, on the surface facing the collector, and wherein a region exists adjacent to and touching the collector where the motion of the fibers is governed by the potential difference between the nanofibers and the collector and is unaffected by the shaping air flow.

Assignees

• Du Pont

Inventors

• Huang Tao
• Armantrout Jack Eugene
• Harding Thomas William
• Daly Thomas Patrick
• Croft Jay J
• Saquing Carl
• Catlin Glenn Creighton

Classifications

• D04H1/732

  by fluid current, e.g. air-lay · CPC title

• D01D5/18

  by means of rotating spinnerets · CPC title

• D10B2331/04

  polyesters, e.g. polyethylene terephthalate [PET] · CPC title

• D01D10/00

  Physical treatment of artificial filaments or the like during manufacture, i.e. during a continuous production process before the filaments have been collected (finishing D02J) · CPC title

• D04H1/736

  characterised by the apparatus for arranging fibres (D04H1/728, D04H1/732 take precedence) · CPC title