PURPOSE: The titled composition that contains a specific oil-modified alkyd resin and a compound having an ethylenically unsaturated bond as a curing component, thus being suitably used as an anticorrosive primer coating for steel pipe with high anticorrosive, antiweathering and alkali degreasing properties.
CONSTITUTION: (A) 5W35pts. wt. of an oil-modified alkyl resin of 20W80% oil length and 10W60 acid value, which is obtained by using an oil selected from drying oils and drying fatty acids, (B) 5W50 pts. of an ethylenically unsaturated compound resulting from the addition reaction between an epoxy group-containing compound and a carboxylic acid containing an ethylenically unsaturated bond, (C) 20W 70pts. of a compound containing an ethylenically unsaturated bond other than component B, (D) 2W20pts. of a photosensitizer or photopolymerization initiator and (E) 0.5W15pts. of an amine as an auxiliary sensitizer are included as essential components so that the total amount of component A through E becomes 100pts. to produce the objective composition.