How to Remove Residual Additives and Low-Molecular Substances in the Coating During the Production of PTFE High-Temperature Cloth

Jiangsu Aokai New Materials – PTFE High-Temperature Cloth Manufacturer, shows you how. During the production of high-quality PTFE high-temperature cloth, residual additives and low-molecular substances in the coating are key factors affecting the final heat resistance, release property and food safety of the product. To ensure the performance of PTFE high-temperature cloth meets standards, a strict multi-stage process is essential to remove these impurities.

Primary Stage: Core Thermal Treatment Purification for PTFE High-Temperature Cloth Coating

This is the most critical process in PTFE high-temperature cloth production, which achieves physical separation of coating impurities through precise temperature control.

After the PTFE emulsion impregnation of the PTFE high-temperature cloth substrate, the product first enters a low-temperature drying oven. For the wet film on the surface, the temperature is normally controlled at 240–285°C. This step does not aim to form the coating film, but to volatilize moisture, solvents and surfactants in the coating gaps via hot air. Skipping this stage and directly conducting high-temperature sintering will cause pinholes or bubbles on the surface, severely damaging the compactness of the PTFE high-temperature cloth.

Subsequently, the PTFE high-temperature cloth enters a high-temperature zone of 360–380°C. At this temperature, PTFE particles on the surface begin to melt and flow, forming a continuous protective film. Meanwhile, this temperature above the PTFE melting point provides sufficient kinetic energy for residual oligomers and unreacted monomers inside the coating to vaporize and escape from the substrate. Precise control of the sintering temperature is critical to the cleanliness of the PTFE high-temperature cloth:

· Temperatures below 360°C lead to incomplete volatilization of internal impurities;

· Temperatures above 390°C cause the breakdown and decomposition of PTFE molecular chains, contaminating the coating instead.

Secondary Stage: Fine Process Control in PTFE High-Temperature Cloth Production

In addition to core thermal treatment, detailed control during production also helps improve the cleanliness grade of the PTFE high-temperature cloth.

· Substrate Pretreatment: Before coating, the fiberglass cloth used for PTFE high-temperature cloth undergoes thorough dewaxing and degumming treatment. Organic residues on the base fabric will carbonize during subsequent heating and remain in the interlayer, forming persistent defects that cannot be eliminated.

· Auxiliary Cleaning: For PTFE high-temperature cloth requiring high cleanliness, online cleaning with specific solvents or ultrasonic treatment can be applied to semi-finished products, enhancing the removal of surface dust and processing oil stains.

Tertiary Stage: Source Control Strategy for PTFE High-Temperature Cloth Production

The ideal purification method is to intercept impurities before they enter the product system, which requires PTFE high-temperature cloth suppliers to establish strict source control standards.

· High-Quality Raw Material Selection: Only high-purity PTFE dispersion resins with a purity of no less than 99.9% must be used as coating raw materials. Low-grade resins contain excessive low-molecular substances, making it impossible to produce qualified PTFE high-temperature cloth no matter how sintering is optimized later.

· Auxiliary Agent Control: When lubricants or leveling agents are necessary in coating formulation, low-boiling, highly volatile types shall be selected, and their dosage strictly controlled to ensure complete elimination from the finished product.

· Clean Production Environment: The production workshop shall maintain positive pressure and cleanliness. Equipment interiors are lined with PTFE or made of stainless steel to prevent dust and debris from the environment or equipment abrasion from falling into the wet film and forming colored impurity spots in the coating.

The core of removing residual substances in PTFE high-temperature cloth coatings lies in the precise control of sintering temperature and heating curve. Only by combining thermal treatment with full-process cleanliness control can the finished PTFE high-temperature cloth deliver excellent non-stick, heat-resistant and high-insulation properties.

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

For detailed parameters, application scenarios and customized solutions of our full product range including PTFE high-temperature cloth, PTFE high-temperature tape, PTFE high-temperature mesh belt, seamless belt for bonding machines, single-sided PTFE cloth, high-temperature resistant conveyor belts and high-temperature fiberglass cloth, please feel free to contact us via:

Service Hotline:Mr. Guo 18944819998   Mr. Liu 13705266308