Complete Industrial Production Process of PTFE Emulsion Impregnated Fiberglass Cloth

Jiangsu Aokai New Materials, a PTFE high-temperature fabric manufacturer, takes you through the full process.

PTFE high-temperature fabric, chemically known as polytetrafluoroethylene (PTFE) coated fiberglass cloth, is an outstanding polymer composite material. Its production is not a simple coating process, but a sophisticated thermal and chemical treatment system. To produce high-quality PTFE high-temperature fabric, a strict four-stage procedure is required: base fabric preparation, impregnation solution preparation, core impregnation and sintering, and post-treatment.

Stage 1: Pretreatment of the Base Fabric

This stage determines the mechanical strength and structural integrity of the final PTFE fabric.

Thermal Cleaning (Dewaxing)The fiberglass yarn used for weaving PTFE fabric contains organic sizing agents during manufacturing. If not removed, these agents severely hinder adhesion of subsequent PTFE coatings. Therefore, the first step is to feed the base fabric into a high-temperature furnace (approx. 350°C) for rapid dewaxing to ensure cleanliness of the fiberglass substrate.

Surface ModificationTo improve bonding strength between fiberglass and PTFE coating resin, the base fabric is treated with a silane coupling agent. This step significantly enhances interlaminar peel strength and prevents delamination or coating peeling in the finished product.

Stage 2: Preparation of PTFE Impregnation Emulsion

The physical and chemical properties of the final fabric are largely determined at this stage.

· Emulsion MixingThe core raw material is concentrated PTFE dispersion. According to different application requirements — such as high non-stick performance for food baking fabrics or high wear resistance for release fabrics — fillers and additives are precisely added into the emulsion. The formulated impregnation solution is critical to defining the grade of the finished PTFE fabric.

Stage 3: Core Impregnation and Sintering

This is the key process that gives PTFE fabric its exceptional performance, usually involving repeated cycles.

Multiple ImpregnationsUnder constant tension control, the pretreated base fabric passes repeatedly through a dip tank filled with PTFE emulsion. To achieve desired thickness and density, the production line adopts a cyclic process: impregnation → drying → sintering. Each cycle accurately increases the coating weight.

DryingThe impregnated semi-finished fabric passes through a low-temperature oven (approx. 100°C) to gently remove moisture. Improper control at this stage easily causes bubbles or pinholes during sintering, seriously degrading insulation performance.

High-Temperature SinteringThis is the heart of the manufacturing process. The wet coating is sintered at approximately 380°C, allowing PTFE particles to fully melt and flow, forming a dense protective film. The ability of PTFE fabric to withstand long-term service at 260°C comes from polymer chain recrystallization in this step. Incompletely sintered fabric is prone to cracking and loss of non-stick properties.

Stage 4: Post-Treatment and Finished Product Inspection

After sintering, the fabric undergoes further finishing processes.

Hot-Press Setting and Surface TreatmentHigh-end PTFE fabrics (such as those for conveyor belts) are calendered through hot rollers to flatten the surface and relieve internal stress. For PTFE fabrics used in high-frequency copper-clad laminates, special corona treatment is applied to increase surface roughness.

Lamination ProcessFor high-end filtration applications, a thin layer of expanded polytetrafluoroethylene (ePTFE) microporous membrane is laminated onto the surface, creating a composite filter medium with higher filtration efficiency.

Aokai New Materials implements strict quality inspection. Final products are tested using a grammage tester, high-voltage tester, and tensile tester. Only products with uniform thickness, free of pinholes, and compliant with voltage resistance requirements are released as qualified goods.

The above information is provided by Jiangsu Aokai New Materials Technology Co., Ltd.

For detailed specifications, application scenarios and customized solutions of our full product range — including PTFE high-temperature fabrics, PTFE high-temperature tapes, PTFE high-temperature mesh belts, seamless belts for fusing presses, single-sided PTFE fabrics, high-temperature resistant conveyor belts, high-temperature fiberglass fabrics and more — please contact us:

· Service Hotline:Mr. Guo: 18944819998  Mr. Liu: 13705266308