Exhaust gas treatment device
View Patent ↗A mounting mat for an exhaust gas treatment device includes a blend of inorganic fibers and organic nanofibrillated fibers. An exhaust gas treatment device includes a housing and a fragile structure mounted within the housing by the mounting mat that is disposed in a gap between the housing and the fragile catalyst support structure. Additionally disclosed are methods of making a mounting mat for an exhaust gas treatment device and for making an exhaust gas treatment device incorporating the mounting mat.
1. A mounting mat for holding a fragile structure within the housing of an exhaust gas treatment device comprising a blend of inorganic fibers and organic nanofibrillated fibers.
2. The mounting mat of claim 1 , wherein the inorganic fibers are selected from the group consisting of high alumina polycrystalline fibers, ceramic fibers, mullite fibers, glass fibers, biosoluble fibers, quartz fibers, silica fibers, and blends thereof.
3. The mounting mat of claim 2 , wherein the high alumina polycrystalline fibers comprise the fiberization product of about 72 to about 100 weight percent alumina and about 0 to about 28 weight percent silica.
4. The mounting mat of claim 2 , wherein the ceramic fibers comprise alumino-silicate fibers comprising the fiberization product of about 45 to about 72 weight percent alumina and about 28 to about 55 weight percent silica.
5. The mounting mat of claim 2 , wherein the biosoluble fibers comprise magnesia-silica fibers comprising the fiberization product of about 65 to about 86 weight percent silica, from about 14 to about 35 weight percent magnesia and about 5 weight percent of less impurities.
6. The mounting mat of claim 2 , wherein the biosoluble fibers comprise calcia-magnesia-silica fibers comprising the fiberization product of about 45 to about 90 weight percent silica, greater than 0 to about 45 weight percent calcia, and greater than 0 to about 35 weight percent magnesia.
7. The mounting mat of claim 1 , wherein the majority of the organic nanofibrillated fibers have a diameter of less than 1 μm.
8. The mounting mat of claim 1 , wherein greater than 80% of the organic nanofibrillated fibers have diameter of less than 1 μm.
9. The mounting mat of claim 1 , wherein substantially all of the organic nanofibrillated fibers have a diameter of less than 1 μm.
10. The mounting mat of claim 1 , wherein the organic nanofibrillated fibers have an average diameter of from about 50 nm to about 500 nm.
11. The mounting mat of claim 1 , wherein the mat comprises from about 25 weight percent to about 90 weight percent of said inorganic fibers, based on the total weight of the mat.
12. The mounting mat of claim 11 , wherein the mat comprises from about 40 to about 90 weight percent of said inorganic fibers, based on the total weight of the mat.
13. The mounting mat of claim 12 , wherein the mat comprises from about 60 to about 90 weight percent of said inorganic fibers, based on the total weight of the mat.
14. The mounting mat of claim 1 , wherein the mat comprises from about 0.1 weight percent to about 10 weight percent of said organic nanofibrillated fibers, based on the total weight of the mat.
15. The mounting mat of claim 14 , wherein the mat comprises from about 0.25 weight percent to about 5 weight percent of said organic nanofibrillated fibers, based on the total weight of the mat.
16. The mounting mat of claim 14 , wherein the mat comprises from about 0.5 weight percent to about 2.5 weight percent of said organic nanofibrillated fibers, based on the total weight of the mat.
17. The mounting mat of claim 1 , wherein said organic nanofibrillated fibers comprise at least one of acrylic nanofibrillated fibers, natural cellulose nanofibrillated fibers, or regenerated cellulose nanofibrillated fibers.
18. The mounting mat of claim 17 , wherein said mounting mat comprising greater than 0 to about 10 weight percent cellulose nanofibrillated fibers.
19. The mounting mat of claim 1 , wherein said mounting mat comprises an intumescent material.
20. The mounting mat of claim 19 , wherein the intumescent material is selected from the group consisting of unexpanded vermiculite, ion exchanged vermiculite, heat treated vermiculite, expandable graphite, hydrobiotite, water-swelling tetrasilicic flourine mica, alkaline metal silicates, or mixtures thereof.
21. The mounting mat of claim 19 , wherein the intumescent material comprises unexpanded vermiculite.
22. The mounting mat of claim 1 , wherein said mounting mat comprises a clay selected from the group consisting of attapulgite, ball clay, bentonite, hectorite, kyanite, kaolinite, montmorillonite, palygorskite, saponite, sepiolite, silimanite or combinations thereof.
23. The mounting mat of claim 1 , wherein said mounting mat comprises an organic binder different from the organic nanofibrillated fibers.
24. The mounting mat of claim 23 , wherein said organic binder comprises an acrylic latex.