PURPOSE: To prevent a carpet from smudging so simply and efficiently in terms of operability by applying a coating agent, mixing the specified amount of a film making assistant, filler, water and additives at need in an acrylic ester emulsion at specified minimum film making temperature and having this minimum film making temperature lowered to a specified temperature, on one side.

CONSTITUTION: An acrylic ester emulsion of 0.5-7wt% at minimum film making temperature 20-35°C is added to one side of a bituminous damping seat. In addition, a filler 0-50 pt.wt. and a water 70-140 pt.wt. are added to an acrylic ester emulsion 100 pt.wt. (resin solid portion). An additive agent is mixed as much as less than a 15 pt.wt. of total quantity at need in addition, and a coating agent made up of lowering the minimum film making temperature up to 10-25°C is applied on the one side. An application of this coating agent is performed by a flow coater and a roll coater and/or a spray and a brush. Otherwise the bituminous damping seat itself is immersed in the coating agent.