Diisononyl phthalate is widely used as a plasticizer in the production of flexible polyvinyl chloride (PVC) materials. It enhances the flexibility, durability, and workability of PVC, making it suitable for applications such as cables, wires, flooring, and automotive parts. Its compatibility with PVC and ability to improve material performance make it a key component in manufacturing processes. Additionally, it is utilized in coatings, adhesives, and sealants to improve their properties and application efficiency. Its role in creating soft and pliable materials ensures its importance across various industries.