Polyester resins are synthetic materials commonly used in the production of plastics and composites. They are created by combining a polyol and a dicarboxylic acid, resulting in a durable and versatile substance. These resins are known for their resistance to moisture, chemicals, and UV light, making them ideal for various applications, including automotive parts, marine products, and construction materials. In addition to their strength and durability, polyester resins can be easily molded into different shapes, allowing for creative designs. They are often used in conjunction with fiberglass to enhance structural integrity, making them popular in industries such as aerospace and sports equipment manufacturing.