Douglas H Roth

US Patent:

6926961, Aug 9, 2005

Filed:

Aug 15, 2001

Appl. No.:

09/930515

Inventors:

Douglas Duane Roth - Kannapolis NC, US

Assignee:

Invista North America S.a.r.l. - Charlotte NC

International Classification:

D02G003/00

US Classification:

428364, 428373, 55527, 55DIG 39, 252 6254, 442415, 361225

Abstract:

The present invention relates to a blend of 15-97 weight percent electret fibers and 3-85 percent by weight dissimilar non-electret fibers using dry laid blending technique. The electret fibers incorporate 0. 05 to 30 weight percent charge control agents. Optionally, at least about 3 to about 50 weight percent of said blend is bicomponent fibers having a low melting component to bond the blend into a unitary nonwoven structure. The blend is bonded to form nonwoven webs that are used in making filter fabric and particularly air filter fabric. The charge control agents are selected from the class of triphenylmethanes; ammonium and immonium compounds; fluorinated ammonium and immonium compounds; bis-cationic acid amides; polymeric ammonium compounds; diallylammonium compounds; arylsulfide derivatives; phenol derivatives; phosphonium compounds and fluorinated phosphonium compounds; calix(n)arenes; metal complex compounds; benzimidazolones; and azines, thiazines or oxazines which are listed in the Color Index as Pigments, Solvent Dyes, Basic Dyes or Acid Dyes. The preferred blend contains electret fibers of polypropylene with one or more charge control agents and polyethylene terephthalate fibers having no charge control agents.

US Patent:

46053646, Aug 12, 1986

Filed:

Jan 25, 1985

Appl. No.:

6/680452

Inventors:

Douglas D. Roth - Matthews NC
Fredrick A. Ethridge - Waxhaw NC

Assignee:

Celanese Corporation - New York NY

International Classification:

B29D 720

US Classification:

425 72S

Abstract:

A melt-spinning apparatus is disclosed for reducing the birefringence variability of melt-spun yarn made at high pack throughputs. It involves extruding polymer at an average mass-flow rate through a first group of orifices (defined by specific location in the spinnerette), that is greater than the mass-flow rate of polymer through a second group of orifices (also defined by location in the spinnerette). The apparatus comprises a spinneret having concentric rows of orifices and a centrally located quench means, with the diameter, d. sub. 1, of the orifices in the row closest to the quench means being greater than the diameter, d. sub. 2, of the orifices in the row furtherest from the quench means by an amount such that d1/d2 is in the range from 1. 03 to 1. 20.

US Patent:

45143501, Apr 30, 1985

Filed:

Sep 23, 1982

Appl. No.:

6/422116

Inventors:

Douglas D. Roth - Matthews NC
Fredrick A. Ethridge - Waxhaw NC

Assignee:

Celanese Corporation - New York NY

International Classification:

B29F 304

US Classification:

264176F

Abstract:

A melt-extrusion process is disclosed for reducing the birefringence variability of melt-spun yarn made at high pack throughputs. It involves extruding polymer at an average mass-flow rate through a first group of orifices (defined by specific location in the spinnerette), that is greater than the mass-flow rate of polymer through a second group of orifices (also defined by location in the spinnerette). It is preferred that a spinnerette be used in which the dimensions of the orifices differ from group to group in a defined manner.