AbstractThe present paper deals with studies concerned with an optimization of the synthesis of urethane‐acrylic UV‐cured resins intended for application as protective coatings for optical fibers. Oligoetherdi‐ and triols, toluylene diisocyanate and isophorone diisocyanate, as well as hydroxyethyl methacrylate and hydroxypropyl methacrylate were used for synthesis. Active diluents butyl acrylate, 2‐ethylhexyl acrylate, 1,4‐butanediol diacrylate or their mixtures, and 2,2‐dimethoxy‐2‐phenylacetophenone as a photoinitiator were added to the urethane‐acrylic dimers comprising polymerization‐active double bonds. The compositions were characterized by the determination of density, viscosity, refractive index, gel content, glass transition temperature, Shore hardness, Young's modulus, breaking stress, relative elongation at break, thermal resistance and water vapour diffusion coefficient before and after curing.The utility of these compositions for protective intermediate coatings of optical fibers was checked and confirmed under manufacturing conditions.