Abstract Selected samples of commercial acrylic resins used for protection and consolidation of different substrates have been characterized in terms of their chemical structures and compositions. Resin compositions were determined from analysis of the products obtained under controlled thermal decomposition of the samples, whereas the amounts of different components were established by NMR spectroscopy. Several resins were formed by two different structural units, whereas the others contain a third component, although in low quantities. The elution behavior of the samples in adsorption liquid chromatography confirmed that the two-component resins are binary random copolymers. As to the ternary samples, it appears that they are either ternary copolymers or mixtures of two different binary copolymers having one monomeric unit in common. It is also shown that the different protective acrylic resins may be distinguished by their refractive indexes and thermogravimetric behavior.