Circumference coating material, bonding material, honeycomb structure, and method of producing honeycomb structure

A method of producing a honeycomb structure comprising:

• at least any one of a circumferential wall forming process in which a circumference coating material is applied to a circumferential surface of a honeycomb structure to fill a recessed groove opened to the outside and extending in an axial direction and to cover the circumferential surface, thereby forming a circumferential wall on the circumferential surface and a bonding process in which a plurality of honeycomb fired bodies formed into a quadrangular pillar-shape are bonded to each other in combination with a bonding material, thereby forming a block-shaped honeycomb structure;
• a drying process of drying the at least one of the circumference coating material and bonding material;
• and
• a heating process of performing a heating treatment at a heating temperature of 600° C. or more on the honeycomb structure formed through the circumferential wall forming process and/or the bonding process,
• wherein the circumference coating material includes colloidal silica in a part of raw materials to be used and has a chlorine concentration after drying of 150 ppm or less, and the bonding material includes colloidal silica in a part of raw materials to be used and has a chlorine concentration after drying of 150 ppm or less, and
• wherein the honeycomb structure subjected to the heating process has a chlorine concentration of 100 ppm or less.