The viscosity herein is a value obtained after the rotation at 25??C for 1 minute at 60 rpm, using in combination, a rotor No.M2 when measuring a viscosity of not lower than 80 mPa??s and not greater than 300 mPa??s; a rotor No.M1 when measuring a viscosity of not lower than 15 mPa??s and lower than 80 mPa??s; or an L-adaptor when measuring a viscosity of lower than 15 mPa??s.