Method for plugging selected cells in a honeycomb

A method for plugging selected cell channels in a honeycomb structure, the method comprising:

• a. providing a honeycomb structure having a multiplicity of adjoining cell channels extending in a mutually parallel fashion between opposing end faces, the cell channels being formed by a matrix of intersecting porous, thin walls which extend across and between the opposing first and second end faces, the cell channels having open ends at each of the end faces of the honeycomb structure;
• b. covering the first end face of the honeycomb structure with a mask for charging plugging particulate material into a first plurality of cell channels, the mask comprising a body having a plurality of openings extending therethrough from an outer face thereof to an opposing face thereof positioned juxtaposed the first end face of the honeycomb structure, the openings being sized and positioned across the body to expose therethrough open ends of the first plurality of cell channels;
• c. loading powdered plugging material comprising particulate sealant, from the mask outer face through the mask openings into the first plurality of cell channels having open cell ends adjacent the first end face of the honeycomb structure, wherein the particulate sealant consists essentially, by weight, of 70 to 90% ceramic blend, the ceramic blend being raw ceramic materials selected to form a composition consisting essentially of in percent by weight 12 to 16% MgO, 33 to 38% Al2O3, and 49 to 54% SiO2, which will form cordierite (2MgO.2Al2O3.5SiO2) on firing, and 10 to 30% non-aqueous binder comprising a polymer selected from the group consisting of high molecular weight thermoplastic polymer and thermosetting resin;
• d. passing the powdered plugging material through the length of the first plurality of cells to reach the cell ends opposing the first end face and adjacent the second end face of the honeycomb structure;
• e. forming plugs in the first plurality of cell channels at the cell ends opposing the first end face and adjacent the second end face of the honeycomb structure;
• f. loading powdered plugging material into the open ends of a second plurality of cell channels, the second plurality of cell channels corresponding to cell channels having open ends at the second end face of the honeycomb structure;
• g. passing the powdered plugging material through the length of the second plurality of cells to reach the cell ends opposing the second end face and adjacent the first end face of the honeycomb structure;
• and,
• h. forming plugs in the second plurality of cell channels at cell ends opposing the second end face and adjacent the first end face of the honeycomb structure.