Silicone resins, such as the hydroxy functional 26018 (Dow Corning), can be used at up to 20% to enhance the exterior durability of a coating. Normally, however, a reduction in film flexibility is observed.
Often non reactive plasticisers, such as saturated polyester adipates or epoxidised soya bean oils, are added in small quantities to thermosetting acrylics to improve the flexibility or drawing properties of the coating.