Polyester resins are the unsaturated synthetic resins made by the reaction of polyhydric alcohols and dibasic organic acids. These are known for the diacid functionality and are applicable for bulk molding compound, sheet molding compound and toner of many laser printers. Polyester resins have adequate resistance to chemicals as well as water. They are high-density and transparent polymers, supplied with excellent strength as well as water resistance. Also, these find usage in textiles as well as packaging sector. The resins have resistance to ageing, weathering etc. These can be used in combination with several strengthening materials.