SYNTEVEN 432 is an unsaturated polyester resin dissolved in styrene, pre-accelerated with an amine accelerator, extremely reactive, and highly stabilized. SYNTEVEN 432 is used as a single binder for the formulation of fillers with good adhesion characteristics on various types of supports, in particular for those intended for knife fillers in the OEM automotive and Car Refish sectors. SYNTEVEN 432, after the addition of benzoyl peroxide (BPO), hardens cold even at very low temperatures, giving rise to a polymer of medium hardness. Fillers formulated with SYNTEVEN 432 harden completely even at high thicknesses and are suitable for applications where good adhesion, rapid drying, and short sanding times are required. We recommend the use of appropriate fillers and extenders such as talc, dolomite/calcite, crystalline gypsum, and iron-free barites; talc, considering its property of improving the sandability and adhesion characteristics of the substrate, should represent the main component. Furthermore, fillers with a more spherical shape such as dolomite and barite ensure greater compactness to the product. However, to avoid unexpected incompatibility phenomena we recommend carrying out preliminary tests.