Process for manufacturing a component for a catalytic converter

A process for manufacturing a component for a catalytic converter, comprising taking a ceramic unit prepared by extruding green ceramic product through a die to form an extrusion having a honeycomb substrate structure having a regular array of parallel, linear tubular passages extending along the length of the extrusion, the passages bounded by walls dividing adjacent passages from one another, the ceramic unit being obtained by cutting off a length of the extrusion and curing and firing the cut off length of extrusion, the process further comprising, following the firing, injecting low viscosity insulation material from an end of the ceramic unit into selected ones of the elongate passages so as to block the selected passages over at least a part of the lengths thereof while maintaining all of the walls of the ceramic unit, and curing the injected insulation material to form a thermally insulating barrier, extending over at least a part of the length of the ceramic unit and extending continuously around a central axis of the ceramic unit between a radially inner zone and a radially outer zone thereof, wherein, passages in the inner and outer zones are free of such insulation material, wherein the maintained walls include walls crossing the insulating barrier, and wherein the insulation material in at least some of the passages is injected from said one end to fill the selected passages to the other end of the ceramic unit.