SYNTEVEN 720 is an allyl unsaturated polyester resin dissolved in styrene of the “direct gloss” type with characteristics of good reactivity and rapid hardening, cross-linked with U.V. after the addition of specific photoinitiators. It is particularly suitable for formulating easily sandable primers and transparent or pigmented finishes, with good surface hardness and scratch resistance. It is compatible with polyesters of the SYNTEVEN series to increase film flexibility.