Mounting mat for exhaust gas treatment device

Abstract

Disclosed is a mat or molded pre-form that may be used as a mounting mat to mount a fragile monolith within an outer housing of an exhaust gas treatment device, such as automotive catalytic converters and diesel particulate traps. The mat or pre-form may also be used as thermal insulation in the end cone regions of the exhaust gas treatment device. The mat and pre-form includes an inorganic microporous insulation component and a flexible fibrous material component. Exhaust gas treatment devices and methods for making exhaust gas treatment devices including the mat or pre-form are also disclosed.

1 . An exhaust gas treatment device comprising:
 a housing;   a fragile structure located within the housing; and   a mounting mat disposed between the housing and the fragile structure, said mounting mat comprising a single or multiple layer mounting mat comprising microporous inorganic insulating material and a flexible fibrous material, wherein the microporous inorganic insulating material is shielded from exposure to liquid or liquid vapor.   
     
     
         2 . A multiple layer mounting mat comprising microporous inorganic insulating material and a flexible fibrous material, wherein the microporous inorganic insulating material is shielded from exposure to liquid or liquid vapor, wherein
 the flexible fibrous material comprises a first layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter;   the flexible fibrous material comprises a second layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter;   the microporous inorganic insulating material is sealed entirely within the perimeters of the first layer and the second layer, and   wherein both of the first layer and the second layer are intumescent.   
     
     
         3 . A multiple layer mounting mat comprising microporous inorganic insulating material and a flexible fibrous material, wherein the microporous inorganic insulating material is shielded from exposure to liquid or liquid vapor, wherein
 the flexible fibrous material comprises a first layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter;   the flexible fibrous material comprises a second layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter;   the microporous inorganic insulating material is sealed entirely within the perimeters of the first layer and the second layer, and   wherein the first layer is either non-intumescent or intumescent and, if the first layer is intumescent then the second layer is non-intumescent, or if the first layer is non-intumescent then the second layer is intumescent.   
     
     
         4 . An exhaust gas treatment device comprising:
 a housing;   a fragile structure located within the housing; and   a mounting mat disposed between the housing and the fragile structure, the mounting mat comprising a multiple layer mounting mat comprising microporous inorganic insulating material and a flexible fibrous material, wherein the microporous inorganic insulating material is shielded from exposure to liquid or liquid vapor, wherein   the flexible fibrous material comprises a first layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter;   the flexible fibrous material comprises a second layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter; and   the microporous inorganic insulating material is sealed entirely within the perimeters of the first layer and the second layer.   
     
     
         5 . A multiple layer mounting mat comprising microporous inorganic insulating material and a flexible fibrous material, wherein the microporous inorganic insulating material is shielded from exposure to liquid or liquid vapor, wherein
 the flexible fibrous material comprises a first layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter;   the flexible fibrous material comprises a second layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter; and   the microporous inorganic insulating material has an outer perimeter that is substantially coextensive with the perimeters of the first layer and the second layer, wherein the microporous inorganic insulation material is positioned between the first layer and the second layer and wherein edges of the microporous inorganic insulation mat are coated with a hydrophobic coating.   
     
     
         6 . The multiple layer mounting mat of  claim 5 , wherein both of the first layer and the second layer are non-intumescent. 
     
     
         7 . The multiple layer mounting mat of  claim 5 , wherein both of the first layer and the second layer are intumescent. 
     
     
         8 . The multiple layer mounting mat of  claim 5 , wherein the first layer is either non-intumescent or intumescent and, if the first layer is intumescent then the second layer is non-intumescent, or if the first layer is non-intumescent then the second layer is intumescent. 
     
     
         9 . The multiple layer mounting mat of  claim 5 , wherein the microporous inorganic insulation layer comprises a first major surface and a second major surface, and wherein either or both of the first major surface and the second major surface are at least partially coated with a hydrophobic coating prior to being positioned between the first layer and the second layer. 
     
     
         10 . An exhaust gas treatment device comprising:
 a housing;   a fragile structure located within the housing; and
 the mounting mat of  claim 5  disposed between the housing and the fragile structure. 
   
     
     
         11 . An end cone for an exhaust gas treatment device comprising:
 an outer metallic cone;   an inner metallic cone; and   cone insulation disposed between the outer and inner metallic cones, the cone insulation comprising the mounting mat of  claim 5 .   
     
     
         12 . An end cone for an exhaust gas treatment device comprising:
 an outer metallic cone; and   self-supporting cone insulation comprising the mounting mat of  claim 5  disposed adjacent the inner surface of the outer metallic cone.   
     
     
         13 . A multiple layer mounting mat comprising microporous inorganic insulating material and a flexible fibrous material, wherein the microporous inorganic insulating material is shielded from exposure to liquid or liquid vapor, wherein
 the flexible fibrous material comprises a first layer comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite the first major surface and an outer perimeter; and   the microporous inorganic insulating material has a first major surface and a second major surface opposite the first major surface and an outer perimeter that is substantially coextensive with the perimeter of the first layer, wherein one of the first or second major surfaces and lateral edges of the microporous inorganic insulation mat are coated with a hydrophobic coating.   
     
     
         14 . The multiple layer mounting mat of  claim 13 , wherein the first layer is non-intumescent. 
     
     
         15 . The multiple layer mounting mat of  claim 13 , wherein the first layer is intumescent. 
     
     
         16 . The multiple layer mounting mat of  claim 15 , wherein, when the first major surface of the microporous inorganic insulation layer is coated with a hydrophobic coating, the second major surface of the microporous inorganic insulation layer is at least partially coated with a hydrophobic coating prior to constructing the multiple layer mounting mat, and when the second major surface of the microporous inorganic insulation layer is coated with a hydrophobic coating, the first major surface of the microporous inorganic insulation layer is at least partially coated with a hydrophobic coating prior to constructing the multiple layer mounting mat. 
     
     
         17 . An exhaust gas treatment device comprising:
 a housing;   a fragile structure located within the housing; and
 the mounting mat of  claim 13  disposed between the housing and the fragile structure. 
   
     
     
         18 . An end cone for an exhaust gas treatment device comprising:
 an outer metallic cone;   an inner metallic cone; and   cone insulation disposed between the outer and inner metallic cones, the cone insulation comprising the mounting mat of  claim 13 .   
     
     
         19 . An end cone for an exhaust gas treatment device comprising:
 an outer metallic cone; and   self-supporting cone insulation comprising the mounting mat of  claim 13  disposed adjacent the inner surface of the outer metallic cone.