Non-respirable, polycrystalline, aluminosilicate ceramic filaments, fibers, and nonwoven mats, and methods of making and using the same

Patent metadata

Field	Value
Publication number	US-2020002861-A1
Application number	US-201716461395-A
Country	US
Kind code	A1
Filing date	Nov 8, 2017
Priority date	Nov 18, 2016
Publication date	Jan 2, 2020
Grant date	—

Abstract

A nonwoven web including a multiplicity of non-respirable, polycrystalline, aluminosilicate ceramic filaments entangled to form a cohesive mat, the polycrystalline, aluminosilicate ceramic filaments having an average mullite percent of at least 75 wt. %. The cohesive mat preferably exhibits a compression resilience after 1,000 cycles at 900° C. when measured according to the Fatigue Test, of at least 30 kPa. Insulation articles including the cohesive mats or formed by chopping the ceramic mats into ceramic fibers, pollution control devices including the insulation articles, and methods of making the non-respirable, polycrystalline, aluminosilicate ceramic filaments and fibers, nonwoven webs, insulation articles, and pollution control devices, are also described.

First claim

1 . A nonwoven article, comprising:
a plurality of non-respirable, polycrystalline, aluminosilicate ceramic filaments entangled to form a cohesive nonwoven mat, wherein the aluminosilicate ceramic filaments have an average mullite percent of at least 75 wt. %, optionally wherein the cohesive mat exhibits a compression resilience of at least 30 kPa after 1,000 cycles at 900° C. when measured according to the Fatigue Test using the open gap setting.

2 . The nonwoven article of claim 1 , wherein each of the plurality of non-respirable, polycrystalline, aluminosilicate ceramic filaments exhibits a diameter of at least 3 micrometers as determined using the Filament Diameter Measurement Procedure with electron microscopy.

3 . The nonwoven article of claim 1 , wherein the plurality of non-respirable, polycrystalline, aluminosilicate ceramic filaments exhibit at least one of a Process Capability Index (Cpk) for fiber diameters greater than three micrometers of at least 1.33, or a Process Performance Index (Ppk) for fiber diameters greater than three micrometers of at least 1.33, as determined using the Filament Diameter Measurement Procedure with electron microscopy.

4 . The nonwoven article of claim 1 , further comprising fibers selected from the group consisting of alumina fibers, silica fibers, silicon carbide fibers, silicon nitride fibers, carbon fibers, glass fibers, metal fibers, alumina-phosphorous pentoxide fibers, alumina-boria-silica fibers, zirconia fibers, zirconia-alumina fibers, zirconia-silica fibers, and mixtures or combinations thereof.

5 . The nonwoven article of claim 1 , wherein the plurality of non-respirable, polycrystalline, aluminosilicate ceramic filaments have an alumina to silica ratio in the range of 60:40 to 90:10 by weight.

6 . The nonwoven article of claim 1 , further comprising a binder to bond together the plurality of non-respirable, polycrystalline, aluminosilicate ceramic filaments, optionally wherein the binder is selected from an inorganic binder, an organic binder, and combinations thereof.

7 . A nonwoven article of claim 1 , wherein the article is selected from the group consisting of a filtration article, a thermal insulation article, an acoustic insulation article, a fire protection article, a mounting mat for a vehicle component, a gasket, a catalyst support, and combinations thereof.

8 . A pollution control device comprising the nonwoven article of claim 7 , optionally wherein the pollution control device is selected from the group consisting of a catalytic converter, a muffler, and combinations thereof.

9 . The pollution control device of claim 8 , further comprising an intumescent layer, a reinforcing mesh, a non-intumescent insert, or a combination thereof.

10 . A method of making a nonwoven web, comprising:
flowing an aqueous ceramic precursor sol through at least one orifice to produce at least one substantially continuous filament, wherein the aqueous ceramic precursor sol comprises at least one of alumina particles or silica particles dispersed in water, and further wherein the aqueous ceramic precursor sol further comprises at least one of a hydrolysable aluminum-containing compound or a hydrolyazable silicon-containing compound; removing at least a portion of the water from the at least one substantially continuous filament to at least partially dry the at least one substantially continuous filament; passing the at least partially dried filament through an attenuator to draw the filaments to a diameter not less than or equal to three micrometers; and collecting the at least partially dried filaments as a nonwoven web on a collector surface.

11 . The method of claim 10 , further comprising directing a stream of gas proximate the at least one substantially continuous filament to at least partially dry the at least one substantially continuous filament, optionally wherein the stream of gas is heated.

12 . The method of claim 10 , wherein the aqueous ceramic precursor sol comprises aluminum chlorohydrate and silica, optionally wherein the aqueous ceramic precursor sol further comprises at least one of a water soluble (co)polymer and a defoamer.

13 . The method of claim 10 , further comprising heating the nonwoven web at a temperature and for a time sufficient to convert the nonwoven web to a cohesive mat comprised of at least one non-respirable, polycrystalline, aluminosilicate ceramic filament having an average mullite percent of at least 75 wt. %, wherein each of the aluminosilicate ceramic filaments has a diameter greater than or equal to three micrometers.

14 . The method of claim 13 , further comprising at least one of needle-punching, stitch-bonding, hydro-entangling, binder impregnation, and chopping of the cohesive mat.

15 . The method of claim 14 , wherein the cohesive mat is chopped to produce a plurality of discrete, non-respirable, polycrystalline, aluminosilicate ceramic fibers wherein the plurality of discrete, non-respirable, polycrystalline, aluminosilicate ceramic filaments each has a diameter of at least three micrometers as determined using the Filament Diameter Measurement Procedure with electron microscopy, the method further comprising at least one of wet-laying or air-laying at least a portion of the discrete non-respirable polycrystalline, aluminosilicate ceramic fibers to form a fibrous ceramic mat, optionally wherein the fibrous ceramic mat exhibits a compression resilience of at least 30 kPa after 1,000 cycles at 900° C. when measured according to the Fatigue Test using the open gap setting.

Assignees

• 3M Innovative Properties Co

Inventors

• De Rovere Anne N
• Mcgee Kari A
• Heller Daimon K
• Chiu William V
• Bekker Petrus J
• Berrigan Michael R

Classifications

• D01F9/08

  of inorganic material (working or processing of metal wire B21F; from softened glass, minerals or slags C03B37/00) · CPC title

• C04B35/18

  rich in aluminium oxide · CPC title

• D04H3/115 Primary

  by applying or inserting filamentary binding elements · CPC title

• C04B2235/5256

  Two-dimensional, e.g. woven structures · CPC title

• D04H3/105

  by needling (needling machines D04H18/00) · CPC title