TOC (Thermal Overcoat, thermally-cured OC) is a core thermally-curable insulating protective film material coated on the lower part of the display (LCD) panel, above the color filter (RGB) and black matrix (BM) layers. It planarizes the step differences between patterns and protects components from chemical agents and thermal stress in subsequent processes. Based on excellent coating uniformity and processability, it suppresses film thickness variation across the substrate and prevents VCD Mura (stains) and color difference. In addition, it provides excellent chemical resistance to chemicals such as solvent NMP used in subsequent processes and reliable adhesion to the substrate, maintaining panel structural stability under assembly and high-temperature post-processing environments while suppressing peeling and cracking. After high-temperature baking, no yellowing or haze occurs; the material features excellent visible light transmittance and low outgassing, contributing to stable mass production yield and extended panel lifetime. It is widely applicable to standard LCDs and the manufacture of small/medium and large panels.