Satyen Polymers offers Unsaturated Polyester Resin Based on Phthalic Anhydride. Satyen Polymers manufactures and supplies Unsaturated Polyester Resin [UPR]. The Unsaturated Polyester Resin Based on Phthalic Anhydride performs best if the laminate is completely cured. The quantity of catalyst and accelerator can be adjusted to get a shorter or longer gel time. The polyester resin remains stable for 3 months at 30°C in the dark and 4 months at 25°C. The resin stability deteriorates markedly at elevated temperature, especially when exposed to direct sunlight.