Abstract: A filter comprising a columnar honeycomb structure part, the columnar honeycomb structure part including: a plurality of first cells each extending from a first bottom surface to a second bottom surface of the columnar honeycomb structure part, the first bottom surface being opened and the second bottom surface being plugged for the plurality of first cells; a plurality of second cells each extending from the first bottom surface to the second bottom surface of the columnar honeycomb structure part, the first bottom surface being plugged and the second bottom surface being opened for the plurality of second cells; and porous cordierite partition walls that define the first cells and the second cells, the partition walls having an average pore depth of 1.5 ?m or more and 3.5 ?m or less as measured by a laser microscope, and a porosity of from 50 to 60% as measured by a mercury porosimeter.

Abstract: A plugged honeycomb structure has a plurality of cells defined by partition walls to become through channels for fluid, one end of each of the predetermined cells is plugged by a plugging member, the other end of each of the residual cells is plugged by the plugging member, the partition wall is made of a cordierite component as a main component, and a value obtained by dividing Young's modulus of a plugging structure portion formed by the partition walls and the plugging member by Young's modulus of a cell structure portion formed by the partition walls is in a range of 1.05 to 2.00.

Abstract: A manufacturing method of a honeycomb structure includes a forming step of preparing a forming raw material containing a cordierite forming material and an inorganic binder, and kneading and forming the prepared forming raw material to have a honeycomb shape; and a firing step of firing the prepared formed body. In the forming step, as the inorganic binder, smectite is used in which at least parts of interlayer metal cations are ion-exchanged with non-metal cations. In the smectite, a total amount of sodium to be contained in the smectite is 1.6 mass % or less in terms of oxides to 100 mass % of the smectite. A content ratio of the smectite in the forming raw material is 0.5 parts by mass or more and 4.0 parts by mass or less to 100 parts by mass of the cordierite forming material.

Abstract: A filter comprising a columnar honeycomb structure part, the columnar honeycomb structure part including: a plurality of first cells each extending from a first bottom surface to a second bottom surface of the columnar honeycomb structure part, the first bottom surface being opened and the second bottom surface being plugged for the plurality of first cells; a plurality of second cells each extending from the first bottom surface to the second bottom surface of the columnar honeycomb structure part, the first bottom surface being plugged and the second bottom surface being opened for the plurality of second cells; and porous cordierite partition walls that define the first cells and the second cells, the partition walls having an average pore depth of 1.5 ?m or more and 3.5 ?m or less as measured by a laser microscope, and a porosity of from 50 to 60% as measured by a mercury porosimeter.

Abstract: A circumferential coating material which is coated on a circumferential surface of a honeycomb structure monolithically formed by extrusion, to form a circumferential coating layer, the circumferential coating material containing fused silica in a range of 20 to 75 mass %, containing a color developing agent in a range of 5 to 50 mass %, containing colloidal silica in a range of 5 to 30 mass %, and further containing a silicon based water repellent agent in a range of 1 to 10 mass % to a total mass of the fused silica, the color developing agent, and the colloidal silica.

Abstract: A manufacturing method of a honeycomb structure includes a forming step of preparing a forming raw material containing a cordierite forming material and an inorganic binder, and kneading and forming the prepared forming raw material to have a honeycomb shape; and a firing step of firing the prepared formed body. In the forming step, as the inorganic binder, smectite is used in which at least parts of interlayer metal cations are ion-exchanged with non-metal cations. In the smectite, a total amount of sodium to be contained in the smectite is 1.6 mass % or less in terms of oxides to 100 mass % of the smectite. A content ratio of the smectite in the forming raw material is 0.5 parts by mass or more and 4.0 parts by mass or less to 100 parts by mass of the cordierite forming material.

Abstract: A circumferential coating material which is coated on a circumferential surface of a honeycomb structure monolithically formed by extrusion, to form a circumferential coating layer, the circumferential coating material containing fused silica in a range of 20 to 75 mass %, containing a color developing agent in a range of 5 to 50 mass %, containing colloidal silica in a range of 5 to 30 mass %, and further containing a silicon based water repellent agent in a range of 1 to 10 mass % to a total mass of the fused silica, the color developing agent, and the colloidal silica.

Abstract: A plugged honeycomb structure has a plurality of cells defined by partition walls to become through channels for fluid, one end of each of the predetermined cells is plugged by a plugging member, the other end of each of the residual cells is plugged by the plugging member, the partition wall is made of a cordierite component as a main component, and a value obtained by dividing Young's modulus of a plugging structure portion formed by the partition walls and the plugging member by Young's modulus of a cell structure portion formed by the partition walls is in a range of 1.05 to 2.00.