US Patent 10005418 Seatback side and base material for seatback side

A base material for a seatback side includes a body portion including a protruding portion. The protruding portion has a plate piece surface of a distal end extending from the body portion outwardly relative to an outer portion provided on an outer side in a vehicle width direction. The plate piece surface is placed side by side with a flange surface of a flange portion projecting in a peripheral portion of the body. The distal end is sandwiched by a weather strip together with the flange portion.