Surface finishing agents applied to fiberglass fabric before PTFE coating are critical for final PTFE high-temperature cloth performance. Organosilane coupling agents create molecular bridges between inorganic glass fiber and organic PTFE, boosting peel strength from <2 N/cm to 4-8+ N/cm. Proper treatment also enhances heat resistance (260°C+), dielectric performance, and chemical resistance. Untreated fabric leads to delamination, bubbling, and short service life.