In a porous body, a surface layer thickness Ts takes a relatively small value satisfying P≧0.54 Ts (formula (1)), the surface layer thickness Ts being derived by a microstructure analysis using the porous-body data that is prepared through three-dimensional scanning of a region including a surface (inflow plane 61) of the porous body. Here, P denotes a porosity [%] of the porous body, and 0%<P<100% and 0 μm<Ts are assumed. The surface layer thickness Ts is derived as a distance in a thickness direction (X direction) between a surface-layer region start plane 92 in which a straight-pore opening ratio becomes 98% or less for the first time and a surface-layer region end plane 93 in which the straight-pore opening ratio becomes 1% or less for the first time.

In a porous body, a surface layer thickness Ts takes a relatively small value satisfying P≧0.54 Ts (formula (1)), the surface layer thickness Ts being derived by a microstructure analysis using the porous-body data that is prepared through three-dimensional scanning of a region including a surface (inflow plane 61) of the porous body. Here, P denotes a porosity [%] of the porous body, and 0%<P<100% and 0 μm<Ts are assumed. The surface layer thickness Ts is derived as a distance in a thickness direction (X direction) between a surface-layer region start plane 92 in which a straight-pore opening ratio becomes 98% or less for the first time and a surface-layer region end plane 93 in which the straight-pore opening ratio becomes 1% or less for the first time.

A porous ceramic honeycomb body (10) including intersecting walls that form channels (22) extending axially from a first end face to a second end face and layered plugs (62) comprised of a first layer (64) disposed on channel walls and a second layer (66) disposed inward toward an axial center of each respective channel on the first layer. The plugs seal at least one of a first portion of the channels at the first end face and a second portion of channels at the second end face of the porous ceramic honeycomb body.

A porous ceramic honeycomb body (10) including intersecting walls that form channels (22) extending axially from a first end face to a second end face and layered plugs (62) comprised of a first layer (64) disposed on channel walls and a second layer (66) disposed inward toward an axial center of each respective channel on the first layer. The plugs seal at least one of a first portion of the channels at the first end face and a second portion of channels at the second end face of the porous ceramic honeycomb body.

Process for the production of a hydrophobic thermal-insulation moulding, where a hydrophilic thermal-insulation moulding is brought into contact with a hydrophobizing agent in vapour form with formation of a thermal-insulation moulding coated with hydrophobizing agent, and this is then subjected to a press process and during the press process and/or after the press process is reacted with the hydrophobizing agent with formation of the hydrophobic thermal-insulation moulding, where a) the density of the hydrophobic thermal-insulation moulding after the press process and after the reaction with the hydrophobizing agent is from 100 to 250 kg/m.sup.3, and b) the density of the hydrophilic thermal-insulation moulding on contact with the hydrophobizing agent is from 50% to less than 100% of the density of the hydrophobic thermal-insulation moulding.

Process for the production of a hydrophobic thermal-insulation moulding, where a hydrophilic thermal-insulation moulding is brought into contact with a hydrophobizing agent in vapour form with formation of a thermal-insulation moulding coated with hydrophobizing agent, and this is then subjected to a press process and during the press process and/or after the press process is reacted with the hydrophobizing agent with formation of the hydrophobic thermal-insulation moulding, where a) the density of the hydrophobic thermal-insulation moulding after the press process and after the reaction with the hydrophobizing agent is from 100 to 250 kg/m.sup.3, and b) the density of the hydrophilic thermal-insulation moulding on contact with the hydrophobizing agent is from 50% to less than 100% of the density of the hydrophobic thermal-insulation moulding.

A method of plugging a honeycomb body includes mixing a plugging mixture at a mixing temperature, wherein the plugging mixture comprises a plurality of inorganic particles, inorganic binder, organic binder, and water; dispensing the plugging mixture into a patty mold at a dispensing temperature; cooling the plugging mixture within the patty mold to a cooled temperature, such that a cement patty is formed; and pressing the cement patty into a plurality of channels in a honeycomb body, wherein the mixing temperature and the dispensing temperature are above a hydration point temperature of the organic binder in the plugging mixture, and the cooled temperature is below the hydration point temperature of the organic binder in the plugging mixture.

A method of plugging a honeycomb body includes mixing a plugging mixture at a mixing temperature, wherein the plugging mixture comprises a plurality of inorganic particles, inorganic binder, organic binder, and water; dispensing the plugging mixture into a patty mold at a dispensing temperature; cooling the plugging mixture within the patty mold to a cooled temperature, such that a cement patty is formed; and pressing the cement patty into a plurality of channels in a honeycomb body, wherein the mixing temperature and the dispensing temperature are above a hydration point temperature of the organic binder in the plugging mixture, and the cooled temperature is below the hydration point temperature of the organic binder in the plugging mixture.

A honeycomb structure including a plurality of porous honeycomb block bodies bound via joining material layers A. Each of the porous honeycomb block bodies includes a plurality of porous honeycomb segments bound via joining material layers B, each of the porous honeycomb segment includes: partition walls that defines a plurality of cells to form flow paths for a fluid, each of cells extending from an inflow end face that is an end face on a fluid inflow side to an outflow end face that is an end face on a fluid outflow side; and an outer peripheral wall located at the outermost periphery. At least a part of the joining material layers A has higher toughness than that of the joining material layers B.

A honeycomb structure including a plurality of porous honeycomb block bodies bound via joining material layers A. Each of the porous honeycomb block bodies includes a plurality of porous honeycomb segments bound via joining material layers B, each of the porous honeycomb segment includes: partition walls that defines a plurality of cells to form flow paths for a fluid, each of cells extending from an inflow end face that is an end face on a fluid inflow side to an outflow end face that is an end face on a fluid outflow side; and an outer peripheral wall located at the outermost periphery. At least a part of the joining material layers A has higher toughness than that of the joining material layers B.