Alkyd resins which have the same overall chemical composition and the same degree of polymerization have been prepared from synthetic mixtures of mono-, di-, and triglycerides of linoleic acid, glycerol, and phthalic anhydride. The properties of these resins differend significantly. Microgel particles are present in all resins, but the quantity and size of the gel particules is a function of the glyceride composition. The concept of microgel is used to explain the solution and film forming properties of these resins. Examination of a range of commercially available alkyd resins has shown that microgel particles are present where the functionality is greater than two.