The study is intended to develop new adhesives for pressure-sensitive tapes. Two types of resin acids-modified resins were prepared: (i) Aniline-formaldehyde novolac-type resins were prepared from aniline and formaldehyde under acid catalysis conditions; N,N""-dichlorohydrin aniline was made to react with paraformaldehyde and the product was de-hydrochlorinated with NaOH; the aniline-formaldehyde resin was modified with glycidyl esters of resin acids, (ii) The epoxy aniline formaldehyde resin was modified with resin acids. IR (Fig. 1) and 'H NMR spectra (Fig. 2) were recorded and TG curves (Fig. 3, Table 1) were traced for the modified resins; the activation energies of the decomposition were evaluated (Table 1). When used in pressure-sensitive compositions of acrylic type, these polymers, found to carry hydrophenanthrene moieties in the chains, imparted good cohesion strength to pressure-sensitive tapes (Table 2).