Method for producing honeycomb filter and method for producing ceramic filter assembly

Abstract

A method for producing a honeycomb filter includes mixing ceramic particles and a binder to obtain a ceramic raw material slurry. The ceramic raw material slurry is provided into an extruder to obtain a molded honeycomb filter. The molded honeycomb filter includes cell walls extending along a longitudinal direction of the molded honeycomb filter to define cells having a substantially square shape. The molded honeycomb filter is dried using a microwave dryer. A sealing paste is provided in at least one of the cells at one end face of the honeycomb filter to seal the at least one of the cells at the one end face. The sealing paste is dried using a microwave dryer. The dried molded honeycomb filter is sintered.

1 . A method for producing a honeycomb filter, comprising:
 mixing ceramic particles and a binder to obtain a ceramic raw material slurry;   providing the ceramic raw material slurry into an extruder to obtain a molded honeycomb filter, the molded honeycomb filter comprising:
 cell walls extending along a longitudinal direction of the molded honeycomb filter to define cells having a substantially square shape; 
   drying the molded honeycomb filter using a microwave dryer;   providing a sealing paste in at least one of the cells at one end face of the honeycomb filter to seal the at least one of the cells at the one end face;   drying the sealing paste using a microwave dryer; and   sintering the dried molded honeycomb filter.   
     
     
         2 . The method according to  claim 1 , wherein the ceramic particles are α-silicon carbide powders. 
     
     
         3 . The method according to  claim 1 , wherein the honeycomb filter has an average porosity of 30 to 70%. 
     
     
         4 . The method according to  claim 1 , wherein the honeycomb filter has a thermal conductance of 20 to 80 W/mK. 
     
     
         5 . The method according to  claim 1 , wherein the honeycomb filter has an average pore diameter of 1 to 50 μm 
     
     
         6 . The method according to  claim 1 , wherein the honeycomb filter has 20% or more of through pores. 
     
     
         7 . The method according to  claim 1 , wherein a thickness of the cell walls is 0.46 mm or less. 
     
     
         8 . The method according to  claim 1 , wherein a number of the cells per square inch is 120 or more. 
     
     
         9 . The method according to  claim 1 , wherein a specific surface area of grains forming the cell wall is 0.1 m2/g or more. 
     
     
         10 . A method for producing a ceramic filter assembly, comprising:
 preparing a plurality of honeycomb filters by a method including:
 mixing ceramic particles and a binder to obtain a ceramic raw material slurry; 
 providing the ceramic raw material slurry into an extruder to obtain a molded honeycomb filter, the molded honeycomb filter comprising:
 cell walls extending along a longitudinal direction of the molded honeycomb filter to define cells having a substantially square shape; 
 
 drying the molded honeycomb filter using a microwave dryer; 
 providing a sealing paste in at least one of the cells at one end face of the honeycomb filter to seal the at least one of the cells at the one end face; 
 drying the sealing paste using a microwave dryer; and 
 sintering the dried molded honeycomb filter; 
   applying a seal layer forming paste to form a seal layer, to an outer surface of each of the plurality of honeycomb filters;   adhering each of the plurality of honeycomb filters with the seal layer forming paste; and   drying the adhered plurality of honeycomb filters.   
     
     
         11 . The method according to  claim 10 , wherein the seal layer has a thickness of 0.3 to 3 mm. 
     
     
         12 . The method according to  claim 10 , wherein the seal layer has a thermal conductance of 0.1 to 10 W/mK. 
     
     
         13 . The method according to  claim 10 , wherein the seal layer has inorganic fibers, an inorganic binder, an organic binder, and inorganic particles. 
     
     
         14 . The method according to  claim 10 , further comprising:
 cutting a peripheral portion of the dried plurality of honeycomb filters into a predetermined shape.   
     
     
         15 . The method according to  claim 14 , further comprising:
 applying a seal and smoothing paste to an exposed outer surface of the cut plurality of honeycomb filters to form a smoothing.   
     
     
         16 . The method according to  claim 15 , wherein the smoothing layer has a thickness of 0.1 to 10 mm. 
     
     
         17 . The method according to  claim 15 , wherein the seal layer is thinner than the smoothing layer.