Method for manufacturing exhaust gas purification catalyst

A manufacturing method of an exhaust gas purification catalyst that is configured to purify an exhaust gas exhausted from an internal combustion engine, the manufacturing method comprising:

• a step for preparing a base material that comprises an outer cylinder and a honeycomb structure body being arranged at an inside of the outer cylinder and being formed in a manner where the exhaust gas can flow, the honeycomb structure body having a length in a cylinder axis direction being shorter than the outer cylinder, the outer cylinder comprising a flange part protruding toward the cylinder axis direction more than an end surface of the honeycomb structure body on at least one of end parts toward the cylinder axis direction;
• a step for holding the base material to make a cylinder axis of the base material approximately coincide with a vertical direction;
• a step for inserting a partitioning member, which is formed in a cylindrical shape whose outer diameter is smaller than an inner diameter of the outer cylinder, from a top end of the base material, and then arranging so as to make the end surface at an upward side of the honeycomb structure body be opposed to a lower end of the partitioning member;
• a step for supplying a catalyst layer forming slurry, which comprises a catalyst metal, to the partitioning member;
• and
• a step for sucking the catalyst layer forming slurry from a lower end of the base material, wherein
• at the arranging step, the partitioning member is arranged to make a clearance X between the end surface of the honeycomb structure body and the lower end of the partitioning member, which are arranged to be opposite to each other, become equal to or more than 0.5 mm and not more than 2 mm and to make a value of a clearance Y between an inner wall of the flange part of the base material and an outer wall of the partitioning member become equal to or more than 0.5 mm and not more than 2 mm,
• the catalyst layer forming slurry supplied at the supplying step satisfies Formula (1):
• V4≥2500 X;
• and Formula (2):
• V150≤1150X, when a viscosity at a time of a shearing speed being 4 sec−1 is treated as V4 (mPa·s) and the viscosity at a time of a shearing speed being 150 sec−1 is treated as V150 (mPa·s).