PURPOSE: The titled composition that contains a processing oil of natural oil, a cyclopentadiene resin at a specific ratio as the vehicle component, thus showing good drying property and giving coating films of high hardness, adhesion, water and alkali resistances.

CONSTITUTION: (A) 90W40wt%, preferably 85W45wt% of a processing oil made of natural oil, preferably stand oil or boilded oil of 100W300 poise in vicsosity at 25°C and (B) 10W60wt% of a copolymer of less than 600 number-average molecular weight and of 60W130°C, preferably 80W120°C softening point, whichis prepared by copolymerization of cyclopentadiene and a nonpolar vinyl nomomer, preferably a conjugate diolefin such as 1,3-pentadiene, preferably at (65W45)/(35W55) weight ratio, are mixed. Then, the mixture is included as the vehicle component to give the objective composition.