Patent ID: 8435441
Filing Date: 2013-05-07
Classification: B01D,C04B

Abstract:
1. A method for manufacturing a porous ceramic wall flow filter, comprising the steps of: providing an already fired ceramic honeycomb structure defining a plurality of cell channels bounded by porous channel walls that extend longitudinally from an upstream inlet end to a downstream outlet end; selectively plugging an end of at least one predetermined channel with a plugging mixture which exhibits a capillary viscosity less than 8000 Pa-s when measured at a shear rate of 10/sec to form a honeycomb body; and heating the end plugged honeycomb body at a temperature of at least 50° C. for a period of time sufficient to at least substantially remove the liquid vehicle from the plugging mixture; and then firing the selectively plugged honeycomb body to a peak plug firing temperature of at least 400° C., the peak plug firing temperature being lower than a peak firing temperature of the already fired ceramic honeycomb structure, effective to set or cure the plugging material in the at least one selectively plugged channel; wherein the plugging mixture also exhibits an inclined plane flow rate less than 60mm/8min when measured at an angle of 60 degrees; and wherein the plugging mixture comprises: an inorganic batch composition; a binder; a liquid vehicle; and a rheology modifier selected from the group consisting of an oil, a non-ionic surfactant, and combinations thereof; and wherein the rheology modifer comprises a polyethylene glycol 200 dioleate.