The invention relates to a binder resin which is a plastified epoxide-amine adduct P comprising an adduct EA made of epoxide resins E and amines A, optionally modified by incorporation of unsaturated fatty acids F′, which adduct is plastified by incorporation of a fatty acid amide M, or a mixture M′ of the said fatty acid amide M with a glyceride mixture GX which is a mixture of at least two glycerides selected from the group consisting of a triglyceride GT, a diglyceride GD, and a monoglyceride GM, to a process for its preparation, and to a method of use thereof as primer for wood, mineral, and metal substrates.