METHOD OF MAKING POLYMERIC BARRIER COATING TO MITIGATE BINDER MIGRATION IN A DIESEL PARTICULATE FILTER TO REDUCE FILTER PRESSURE DROP AND TEMPERATURE GRADIENTS

摘要

Ceramic honeycomb structures and methods to make the same are disclosed. The structures may be comprised of at least two separate smaller ceramic honeycombs that have been coated with a polymer to create a polymeric barrier coating and adhered together with a cement comprised of inorganic fibers and a binding phase which is comprised of amorphous silicate, aluminite or alumino silicate glass and other inorganic particles. The polymer is selected such that it is penetratable into or covering the pores in the honeycomb structure to form a thin barrier layer thereon to mitigate migration of the inorganic fibers, binding phase and water into the pores. The polymer is adapted to be burned off or decomposed at or below cement and honeycomb skin firing temperatures, or at or below honeycomb operating temperatures during application to create a honeycomb structure that, when formed into an exhaust filter, does not have any undesired pressure drop increase due to cement migration.