Exhaust gas purifying filter and method of manufacturing the same

Abstract

The present invention provides an exhaust gas purifying filter that has an increased contact area, between a catalyst supported on the dividing walls of a honeycomb structural body and particulate matter deposited thereon, and can improve the capacity of the catalyst to oxidize the particulate matter, and a method of manufacturing the same. According to the present invention, the exhaust gas purifying filter 1 comprising the honeycomb structural body 10 made of ceramic and the catalyst 2 supported on the surface of the dividing walls 11 of the honeycomb structural body 10 has void ratio, of the dividing wall 11 of the honeycomb structural body 10 , in a range from 55 to 80%, and the proportion of surface pores is 20% or higher.

1 - 7 . (canceled)  
     
     
         8 . A method of manufacturing an exhaust gas purifying filter comprising a honeycomb structural body made of ceramic and a catalyst supported on the dividing wall surface of said honeycomb structural body, wherein said honeycomb structural body is made by 
 forming a ceramic molding in a honeycomb shape,    coating the dividing wall surface of said ceramic molding with a reaction promoting agent before or after drying said ceramic molding, and then    firing the ceramic molding,    thereby to increase the proportion of surface pores of said dividing walls of said honeycomb structural body.    
     
     
         9 . The method of manufacturing the exhaust gas purifying filter according to  claim 8 , wherein said honeycomb structural body is made of a ceramic including cordierite as the main component, and said reaction promoting agent is talc.  
     
     
         10 . A method of manufacturing an exhaust gas purifying filter comprising a honeycomb structural body made of ceramic and a catalyst supported on the dividing wall surface of said honeycomb structural body, wherein said honeycomb structural body is made by 
 forming a ceramic molding of honeycomb shape,    drying and firing said ceramic molding and then    applying mechanical impact to the surface of said dividing walls thereby to increase the proportion of surface pores.    
     
     
         11 . The method of manufacturing the exhaust gas purifying filter according to  claim 8 , wherein said ceramic molding of honeycomb shape is formed by using a die that has grooves formed in the shape of honeycomb with the grooves having an undulated configuration of an irregular surface, so as to form the dividing walls of the honeycomb structural body with an undulated configuration of an irregular surface.  
     
     
         12 . The method of manufacturing the exhaust gas purifying filter according to  claim 9 , wherein said ceramic molding of honeycomb shape is formed by using a die that has grooves formed in the shape of honeycomb with the grooves having an undulated configuration of an irregular surface, so as to form the dividing walls of the honeycomb structural body with an undulated configuration of an irregular surface.  
     
     
         13 . The method of manufacturing the exhaust gas purifying filter according to  claim 10 , wherein said ceramic molding of honeycomb shape is formed by using a die that has grooves formed in the shape of honeycomb with the grooves having an undulated configuration of an irregular surface, so as to form the dividing walls of the honeycomb structural body with an undulated configuration of an irregular surface.  
     
     
         14 . A method of manufacturing an exhaust gas purifying filter comprising a honeycomb structural body made of ceramic and a catalyst supported on the dividing wall surface of said honeycomb structural body, wherein said honeycomb structural body is made by 
 forming a ceramic molding in a honeycomb shape,    coating the dividing wall surface of said ceramic molding with a reaction promoting agent before or after drying said ceramic molding, and then    firing the ceramic molding, thereby to increase the proportion of surface pores of said dividing walls of said honeycomb structural body,    wherein the void ratio of said dividing walls of said honeycomb structural body is in a range of 55 to 80%, and the proportion of surface pores is 20% or higher.    
     
     
         15 . The method of manufacturing the exhaust gas purifying filter according to  claim 14 , wherein said honeycomb structural body is made of a ceramic including cordierite as the main component, and said reaction promoting agent is talc.  
     
     
         16 . A method of manufacturing an exhaust gas purifying filter comprising a honeycomb structural body made of ceramic and a catalyst supported on the dividing wall surface of said honeycomb structural body, wherein said honeycomb structural body is made by 
 forming a ceramic molding of honeycomb shape,    drying and firing said ceramic molding and then    applying mechanical impact to the surface of said dividing walls thereby to increase the proportion of surface pores,    wherein the void ratio of said dividing walls of said honeycomb structural body is in a range of 55 to 80%, and the proportion of surface pores is 20% or higher.    
     
     
         17 . The method of manufacturing the exhaust gas purifying filter according to  claim 14 , wherein said ceramic molding of honeycomb shape is formed by using a die that has grooves formed in the shape of honeycomb with the grooves having an undulated configuration of an irregular surface, so as to form the dividing walls of the honeycomb structural body with an undulated configuration of an irregular surface.  
     
     
         18 . The method of manufacturing the exhaust gas purifying filter according to  claim 15 , wherein said ceramic molding of honeycomb shape is formed by using a die that has grooves formed in the shape of honeycomb with the grooves having an undulated configuration of an irregular surface, so as to form the dividing walls of the honeycomb structural body with an undulated configuration of an irregular surface.  
     
     
         19 . The method of manufacturing the exhaust gas purifying filter according to  claim 16 , wherein said ceramic molding of honeycomb shape is formed by using a die that has grooves formed in the shape of honeycomb with the grooves having an undulated configuration of an irregular surface, so as to form the dividing walls of the honeycomb structural body with an undulated configuration of an irregular surface.