Granted Patent B2

US 8,734,726 · App. 12/968,873 · Granted May 27, 2014

Abstract

Claims (44)

1. A multilayer mounting mat for an exhaust gas treatment device comprising:

high temperature resistant inorganic fibers;

optionally organic binder; and

optionally an intumescent material;

wherein the mat is formed from multiple plies of wet laid fibrous sheets;

wherein the majority of fibers in each of a plurality of the multiple plies of wet laid fibrous sheets are oriented within the x-y plane of each such fibrous sheet; and

wherein a minor portion of the fibers are physically entangled within the multilayer mounting mat by at least one of wet-needling, dry-needling, hydro-entanglement or pressing.

2. The multilayer mounting mat of claim 1 , wherein the inorganic fibers are at least one of high alumina polycrystalline fibers, refractory ceramic fibers, mullite fibers, alumina-zirconia-silica fibers, alumina-magnesia-silica fibers, glass fibers, high temperature resistant biosoluble fibers, leached glass silica fibers, or combinations thereof.

3. The multilayer mounting mat of claim 2 , wherein the high alumina polycrystalline fibers comprise the fiberization product of from about 72 to about 100 weight percent alumina and from about 0 to about 28 weight percent silica.

4. The multilayer mounting mat of claim 2 , wherein the refractory ceramic fibers comprise alumino-silicate fibers comprising the fiberization product of from about 45 to about 75 weight percent alumina and from about 25 to about 55 weight percent silica.

5. The multilayer mounting mat of claim 2 , wherein the biosoluble fibers comprise magnesia-silica fibers comprising the fiberization product of from about 65 to about 86 weight percent silica, from about 14 to about 35 weight percent magnesia and about 5 weight percent or less impurities.

6. The multilayer mounting mat of claim 2 , wherein the biosoluble fibers comprise calcia-magnesia-silica fibers comprising the fiberization product of from about 45 to about 90 weight percent silica, from greater than 0 to about 45 weight percent calcia, and from greater than 0 to about 35 weight percent magnesia.

7. The multilayer mounting mat of claim 1 , wherein the intumescent material is at least one of unexpanded vermiculite, ion exchanged vermiculite, heat treated vermiculite, expandable graphite, hydrobiotite, water-swelling tetrasilicic flourine mica, alkaline metal silicates, or mixtures thereof.

8. The multilayer mounting mat of claim 7 , wherein the intumescent material comprises unexpanded vermiculite.

9. The multilayer mounting mat of claim 1 , wherein the organic binder comprises at least one of acrylic latex, (meth)acrylic latex, copolymers of styrene and butadiene, vinylpyridine, acrylonitrile, copolymers of acrylonitrile and styrene, vinyl chloride, polyurethane, copolymers of vinyl acetate and ethylene, polyamides, silicones, unsaturated polyesters, epoxy resins and polyvinyl esters, and mixtures thereof.

10. The multilayer mounting mat of claim 1 , wherein the organic binder comprises at least one of polyvinyl alcohol fibers, polyolefin fibers, polyethylene fibers, polypropylene fibers, acrylic fibers, polyester fibers, ethyl vinyl acetate fibers, nylon fibers, and combinations thereof.

11. The multilayer mounting mat of claim 1 , further comprising at least one of colloidal silica, colloidal alumina, colloidal zirconia, or combinations thereof.

12. A process for producing the multilayer mounting mat of claim 1 comprising preparing a wet paper or sheet comprising the high temperature resistant fibers, optionally an organic binders and optionally intumescent material; stacking multiple plies of the wet paper or sheet together, and intertwining or entangling a portion of the fibers between plies within the stack of wet paper or sheet plies prior to drying.

13. The process of claim 12 wherein said intertwining or entangling comprises at least one of needle punching or hydro-entangling the stack of wet paper or sheet plies.

14. An exhaust gas treatment device comprising:

a housing;

a fragile structure resiliently mounted within the housing; and

a mounting mat disposed in a gap between the housing and the fragile structure, wherein the mounting mat is defined in claim 1 .

15. The exhaust gas treatment device of claim 14 , wherein the device is a catalytic converter or diesel particulate trap.

16. An end cone for an exhaust gas treatment device comprising:

an outer metallic cone;

an inner metallic cone; and

cone insulation disposed between said outer and inner metallic end cones, said cone insulation comprising:

high temperature resistant inorganic fibers;

optionally organic binder; and

optionally an intumescent material;

wherein the cone insulation is formed from multiple plies of wet laid fibrous sheets;

wherein the majority of fibers in each of a plurality of the multiple plies of wet laid fibrous sheets are oriented within the x-y plane of each such fibrous sheet; and

wherein a minor portion of the fibers are physically entangled within the cone insulation by at least one of wet-needling, dry-needling, hydro-entanglement or pressing.

17. An end cone for an exhaust gas treatment device comprising:

an outer metallic cone; and

self-supporting cone insulation comprising:

high temperature resistant inorganic fibers;

optionally organic binder; and

optionally an intumescent material;

wherein the cone insulation is formed from multiple plies of wet laid fibrous sheets;

wherein the majority of fibers in each of a plurality of the multiple plies of wet laid fibrous sheets are oriented within the x-y plane of each such fibrous sheet;

wherein the cone insulation is disposed adjacent to the inner surface of said outer metallic end cone; and

wherein a minor portion of the fibers are physically entangled within the cone insulation by at least one of wet-needling, dry-needling, hydro-entanglement or pressing.

Assignments (10)