Precise Control of PTFE Coating Thickness in Fabric Production

As a professional source manufacturer of PTFE high-temperature fabric, Jiangsu Aokai New Materials gives you a detailed explanation. For the process of impregnating glass fiber fabrics (or similar fiber felts/textiles) with PTFE emulsion, the principle of thickness control is similar to the conventional dip-coating method. The main difficulty lies in the porous and uneven structure of fiber substrates. Therefore, the core of thickness control is to balance the micro liquid absorption capacity and macroscopic process parameters with high precision.

1. Emulsion Formula: Determines the base thickness of each coating layer

Solid content and viscosity: Adopt low solid content dispersion (e.g. 45%) to form a thinner coating per pass and reduce the risk of drying cracking. Emulsion viscosity is the key to adjusting fluidity and coating pickup amount.

2. Impregnation Process: Dynamic mechanical balance

Lifting / Squeezing speed: The speed decides the wet film thickness formed by the balance of gravity and viscous force. A higher speed carries more emulsion and forms a thicker wet film.

Impregnation time and fiber pretreatment: Ensure complete wetting and penetration of fibers. Before impregnation, burrs and impurities on the fiber surface must be thoroughly cleaned to guarantee uniform coating and excellent bonding strength.

Multi-pass coating and post-treatment: Achieve target thickness by gradual accumulation. This is the core strategy for reaching the required thickness, normally following the cycle of multiple impregnation — drying — sintering. The recommended single-pass coating thickness is controlled within 0.01mm ~ 0.08mm.

· Drying: 100~150℃ to completely remove moisture.

· Baking: 280~290℃ to eliminate surfactants. Uneven drying and baking will cause cracks, bubbles or pinholes on the coating.

· Sintering: 360~390℃, holding for 30~90 seconds. Sintering is critical for coating forming. Too low temperature leads to poor bonding between coating and fiber; excessively high temperature may cause resin decomposition.

3. Environmental Factors: Indispensable influencing elements

Humidity: Ambient humidity shall be strictly controlled at 40%–60% RH. Too low humidity will cause surface skinning and insufficient internal penetration; too high humidity may result in sagging, pinholes and reduced adhesion.

Workshop cleanliness: Strictly control workshop cleanliness to prevent airborne particles from falling into the impregnation tank or adhering to the undried wet film, which would cause surface defects.

4. Practical Suggestions & Quality Closed-Loop Control

Production guidance: It is recommended to adopt the strategy of low concentration + multiple impregnation passes to accurately control the total coating thickness by adjusting impregnation times. Meanwhile, standardize pre-treatment and post-treatment procedures, which are the foundation of high-quality coating.

Troubleshooting: If coating cracking occurs after sintering, check whether single-pass coating is too thick or drying speed is too fast; if coating adhesion is insufficient, inspect fiber surface cleanliness as well as sintering temperature and holding time.

Quality closed-loop system: Establish a complete production logic:Process parameter control → On-line real-time monitoring → Finished product statistical analysis → Process optimization feedback.PTFE impregnation is a complex physicochemical process with multi-variable coupling. Stable thickness accuracy can only be achieved by building a standardized control system covering emulsion formula, process parameters and environmental conditions, together with matched testing methods.

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

If you need in-depth information on technical parameters, application scenarios and customized solutions for our full product line including PTFE high-temperature fabric, PTFE high-temperature adhesive tape, PTFE high-temperature mesh belt, seamless fusing machine belt, single-sided PTFE coated fabric, high-temperature resistant conveyor belt and high-temperature resistant fiberglass cloth, please feel free to contact us:

· Service Hotline:Mr. Guo: +86 18944819998  Mr. Liu: +86 13705266308

We always uphold the philosophy of professionalism and integrity, and strive to provide you with one-stop overall solutions and thoughtful after-sales service!