A pillar shaped honeycomb structure includes: a porous partition wall that defines a plurality of cells, the cells forming flow paths for a fluid, the cells extending from an inflow end face to an outflow end face; and an outer peripheral wall located at the outermost circumference. The cells include: a plurality of cells A wherein a side of the inflow end face is opened and the outflow end face has a plugged portion; and a plurality of cells B wherein a side of the outflow end face is opened and the inflow end face has a plugged portion, the cells B being arranged alternately with the cells A. One or both of the plugged portion of the cells A and the plugged portions of the cells B contain a magnetic substance and glass.

A pillar shaped honeycomb structure includes: a porous partition wall that defines a plurality of cells, the cells forming flow paths for a fluid, the cells extending from an inflow end face to an outflow end face; and an outer peripheral wall located at the outermost circumference. The cells include: a plurality of cells A wherein a side of the inflow end face is opened and the outflow end face has a plugged portion; and a plurality of cells B wherein a side of the outflow end face is opened and the inflow end face has a plugged portion, the cells B being arranged alternately with the cells A. One or both of the plugged portion of the cells A and the plugged portions of the cells B contain a magnetic substance and glass.

Methods for applying a surface treatment to a plugged honeycomb body comprising porous wall includes: atomizing particles of an inorganic material into liquid-particulate-binder droplets comprised of an aqueous vehicle, a binder material, and the particles, evaporating substantially all of the aqueous vehicle from the droplets to form agglomerates comprised of the particles and the binder material, and depositing the agglomerates onto the porous walls of the plugged honeycomb body, wherein the agglomerates are disposed on, or in, or both on and in, the porous walls. Plugged honeycomb bodies comprising porous walls and inorganic material deposited thereon are also disclosed.

A method for applying a surface treatment to a plugged honeycomb body comprising porous wall includes: mixing particles of an inorganic material with a liquid vehicle and a binder material to form a liquid-particulate-binder stream; mixing the liquid-particulate-binder stream with an atomizing gas, directing the liquid-particulate-binder stream into an atomizing nozzle thereby atomizing the particles into liquid-particulate-binder droplets comprised of the liquid vehicle, he binder material, and the particles; conveying the droplets toward the plugged honeycomb body by a gaseous carrier stream, wherein the gaseous carrier stream comprises a carrier gas and the atomizing gas; evaporating substantially all of the liquid vehicle from the droplets to form agglomerates comprised of the particles and the binder material; depositing the agglomerates onto the porous walls of the plugged honeycomb body; wherein the deposited agglomerates are disposed on, or in, or both on and in, the porous walls.

A scraping device for undried joining material protruding from a segment joint body in which side surfaces of a plurality of pillar-shaped honeycomb structure segments are joined via the undried joining material, the segment joint body having an outer peripheral side surface, a first honeycomb-shaped end surface, and a second honeycomb-shaped end surface located on an opposite side of the first honeycomb-shaped end surface, the scraping device includes a stand for placing the segment joint body; a controller; and a scraping robot comprising at least one scraping spatula configured to be movable in at least one scraping direction along at least one surface of the outer peripheral side surface, the first honeycomb-shaped end surface, and the second honeycomb-shaped end surface while being pressed against the at least one surface.

A scraping device for undried joining material protruding from a segment joint body in which side surfaces of a plurality of pillar-shaped honeycomb structure segments are joined via the undried joining material, the segment joint body having an outer peripheral side surface, a first honeycomb-shaped end surface, and a second honeycomb-shaped end surface located on an opposite side of the first honeycomb-shaped end surface, the scraping device includes a stand for placing the segment joint body; a controller; and a scraping robot comprising at least one scraping spatula configured to be movable in at least one scraping direction along at least one surface of the outer peripheral side surface, the first honeycomb-shaped end surface, and the second honeycomb-shaped end surface while being pressed against the at least one surface.

A honeycomb structure, including: a plurality of pillar shaped honeycomb segments, each of the pillar shaped honeycomb segments including a partition wall and a plugged portion; and a joining layer arranged so as to join side surfaces of the pillar shaped honeycomb segments to each other. The honeycomb structure satisfies the following equations (1) to (3):

y≤1000  (1);

y≤717.92x.sup.−0.095  (2); and

y≥462.4x.sup.−0.153  (3),

in which y is a maximum temperature (° C.) at which the use of the honeycomb structure is accepted, and x is a thermal conduction factor represented by the following equation:

thermal conduction factor=(thermal conductivity of the partition wall×thermal conductivity of the joining layer)/(average thickness of the joining layer×porosity of the partition wall).

A honeycomb structure, including: a plurality of pillar shaped honeycomb segments, each of the pillar shaped honeycomb segments including a partition wall and a plugged portion; and a joining layer arranged so as to join side surfaces of the pillar shaped honeycomb segments to each other. The honeycomb structure satisfies the following equations (1) to (3):

y≤1000  (1);

y≤717.92x.sup.−0.095  (2); and

y≥462.4x.sup.−0.153  (3),

in which y is a maximum temperature (° C.) at which the use of the honeycomb structure is accepted, and x is a thermal conduction factor represented by the following equation:

thermal conduction factor=(thermal conductivity of the partition wall×thermal conductivity of the joining layer)/(average thickness of the joining layer×porosity of the partition wall).

The invention relates to a heat-activatable foamable honeycomb core splice adhesive having improved fire retardancy, particularly with respect to smoke toxicity and smoke opacity (smoke density).

A honeycomb structure includes plugged honeycomb segments, bonding layers and a circumferential wall. The bonding layers includes bottomed-hollow unbonded portions, which extend toward an internal side in an axial direction from an end face of the honeycomb structure, in portions of circumferential bonding layers bonding the honeycomb segments on an outermost circumference. The unbonded portions exist on respective extended lines extending from an intersection of the bonding layers which is closest to a centroid of the end face. An opening length of the unbonded portion is 1 to 10 mm, a ratio of an opening depth of the unbonded portion to a length of the honeycomb segment is 10 to 45%, and a ratio of a distance from the circumferential wall to a point at which an open end of the unbonded portion ends to a length of the circumferential bonding layer is 5 to 100%.