A ceramic honeycomb structure having pluralities of flow paths partitioned by porous cell walls; (a) the cell walls having porosity of 50-60%; and (b) in a pore diameter distribution in the cell walls measured by mercury porosimetry, (i) pore diameters at cumulative pore volumes corresponding to particular percentages of the total pore volume being within specific ranges and having specific relationships; and (ii) the difference between a logarithm of the pore diameter at a cumulative pore volume corresponding to 20% of the total pore volume and a logarithm of the pore diameter at 80% being 0.39 or less, and its production method.

A ceramic honeycomb structure having pluralities of flow paths partitioned by porous cell walls; (a) the cell walls having porosity of 50-60%; and (b) in a pore diameter distribution in the cell walls measured by mercury porosimetry, (i) pore diameters at cumulative pore volumes corresponding to particular percentages of the total pore volume being within specific ranges and having specific relationships; and (ii) the difference between a logarithm of the pore diameter at a cumulative pore volume corresponding to 20% of the total pore volume and a logarithm of the pore diameter at 80% being 0.39 or less, and its production method.

Provided is a honeycomb fired body in which the pressure loss in the initial state where PM has not accumulated is sufficiently low, the strength is sufficiently high, and the heat capacity is not small. The honeycomb fired body of the present invention is a honeycomb fired body including a plurality of cells in each of which one end is plugged and which serve as channels of exhaust gas, and porous cell partition walls that define the cells, wherein the honeycomb fired body is formed of SiC, the plurality of cells include peripheral cells located at an outermost peripheral region of the honeycomb fired body and inner cells located more inward than the peripheral cells, all the inner cells have the same cross-sectional shape that is a rectangle in a plane perpendicular to the longitudinal direction thereof, each peripheral cell is defined by the cell partition walls and an outer wall forming a periphery of the honeycomb fired body, the cell partition walls in contact with the outer wall each have a thick wall region where the wall thickness gradually increases toward the outer wall, the cross-sectional shape of the peripheral cells in a plane perpendicular to the longitudinal direction thereof is a shape formed by reducing the rectangular cross-sectional shape of the inner cells to obtain a reduced rectangle and chamfering or rounding two corners of the reduced rectangle, the cross-sectional area of each peripheral cell in a plane perpendicular to the longitudinal direction thereof is 60 to 80% of the cross-sectional area of each inner cell in a plane perpendicular to the longitudinal direction thereof, the cell partition walls include inter-peripheral-cell cell partition walls each located between the peripheral cells and inter-inner-cell cell partition walls each located between the inner cells, and the minimum thickness of the inter-peripheral-cell cell partition walls is greater than the thickness of the inter-inner-cell cell partition walls.

Provided is a honeycomb fired body in which the pressure loss in the initial state where PM has not accumulated is sufficiently low, the strength is sufficiently high, and the heat capacity is not small. The honeycomb fired body of the present invention is a honeycomb fired body including a plurality of cells in each of which one end is plugged and which serve as channels of exhaust gas, and porous cell partition walls that define the cells, wherein the honeycomb fired body is formed of SiC, the plurality of cells include peripheral cells located at an outermost peripheral region of the honeycomb fired body and inner cells located more inward than the peripheral cells, all the inner cells have the same cross-sectional shape that is a rectangle in a plane perpendicular to the longitudinal direction thereof, each peripheral cell is defined by the cell partition walls and an outer wall forming a periphery of the honeycomb fired body, the cell partition walls in contact with the outer wall each have a thick wall region where the wall thickness gradually increases toward the outer wall, the cross-sectional shape of the peripheral cells in a plane perpendicular to the longitudinal direction thereof is a shape formed by reducing the rectangular cross-sectional shape of the inner cells to obtain a reduced rectangle and chamfering or rounding two corners of the reduced rectangle, the cross-sectional area of each peripheral cell in a plane perpendicular to the longitudinal direction thereof is 60 to 80% of the cross-sectional area of each inner cell in a plane perpendicular to the longitudinal direction thereof, the cell partition walls include inter-peripheral-cell cell partition walls each located between the peripheral cells and inter-inner-cell cell partition walls each located between the inner cells, and the minimum thickness of the inter-peripheral-cell cell partition walls is greater than the thickness of the inter-inner-cell cell partition walls.

Provided is a technique to manufacture a honeycomb structure reducing a width of dimensional difference generated during firing between an end part and a central part and having excellent thermal shock resistance, and the method includes: a honeycomb formed body preparing step of extruding a kneaded material including a cordierite forming raw material A, to prepare a formed body; a plugged honeycomb formed body preparing step of filling cell openings thereof with a plugging material which includes a forming raw material containing a cordierite forming raw material B and resin balloon of 1.0 to 15 mass % and has a difference in firing shrinkage rate of 1.0 to +2.0% from the formed body, to prepare a plugged formed body; and a honeycomb structure preparing step of firing the prepared plugged formed body, to prepare a honeycomb structure provided with porous plugged portions.

Provided is a technique to manufacture a honeycomb structure reducing a width of dimensional difference generated during firing between an end part and a central part and having excellent thermal shock resistance, and the method includes: a honeycomb formed body preparing step of extruding a kneaded material including a cordierite forming raw material A, to prepare a formed body; a plugged honeycomb formed body preparing step of filling cell openings thereof with a plugging material which includes a forming raw material containing a cordierite forming raw material B and resin balloon of 1.0 to 15 mass % and has a difference in firing shrinkage rate of 1.0 to +2.0% from the formed body, to prepare a plugged formed body; and a honeycomb structure preparing step of firing the prepared plugged formed body, to prepare a honeycomb structure provided with porous plugged portions.

Use of porous metal oxide microspheres as light stabilizers for shaped artificial polymer articles, wherein the porous metal oxide microspheres are prepared via a process comprising forming a liquid dispersion of polymer nanoparticles and a metal oxide; forming liquid droplets of the dispersion; drying the droplets to provide polymer template microspheres comprising polymer nanospheres; and removing the polymer nanospheres from the template microspheres to provide the porous metal oxide microspheres.

A method for manufacturing a ceramic product containing silicon carbide, including a step of firing a formed body of a green body containing silicon carbide by transporting the formed body from an inlet to an outlet of a continuous furnace, wherein the continuous furnace includes the inlet, a heating zone, a cooling zone, and the outlet in this order, and a furnace atmosphere in both the heating zone and the cooling zone is an inert gas having an oxygen concentration of 100 ppm by volume or less.

A method for manufacturing a ceramic product containing silicon carbide, including a step of firing a formed body of a green body containing silicon carbide by transporting the formed body from an inlet to an outlet of a continuous furnace, wherein the continuous furnace includes the inlet, a heating zone, a cooling zone, and the outlet in this order, and a furnace atmosphere in both the heating zone and the cooling zone is an inert gas having an oxygen concentration of 100 ppm by volume or less.