Influence of Lubricant Content on PTFE Paste Extrusion Pressure

Lubricant content is one of the most fundamental adjustable variables in PTFE paste extrusion formula, which directly affects the viscosity, fluidity, and internal friction of PTFE dispersion, and further determines the magnitude and stability of extrusion pressure. PTFE paste extrusion relies on volatile hydrocarbon lubricants to disperse PTFE resin particles, reduce inter-particle friction and die wall friction, and realize continuous low-resistance molding. The proportion of lubricant in the paste system has a linear and decisive influence on extrusion pressure, and unreasonable lubricant content will cause abnormal pressure fluctuation, increased production energy consumption, and various product quality defects. Clarifying the influence mechanism of lubricant content on extrusion pressure is crucial for formula optimization and stable process control of PTFE paste extrusion PTFE TUBE.

Under low lubricant content conditions, the PTFE paste has high particle density, serious inter-particle contact friction, and poor overall fluidity. In this state, the extrusion ram needs to apply extremely high pressure to break the static friction between particles and push the material through the die channel. Insufficient lubrication cannot form a uniform lubricating film between PTFE particles and the die wall, resulting in sharp increase of extrusion resistance, continuous high-pressure operation of equipment, increased energy consumption, and serious wear of extrusion dies and equipment components. Meanwhile, excessive internal friction will cause uneven particle flow, easily leading to surface scratches, particle agglomeration, and local density inconsistency of extruded products, reducing product surface quality and mechanical uniformity.

With the gradual increase of lubricant content, a complete and uniform lubricating film is formed between PTFE particles and die walls, which significantly reduces internal and external friction resistance of the paste. The extrusion pressure decreases steadily and tends to be stable, and the material presents uniform laminar flow state in the die channel, which is conducive to high-precision and high-quality product molding. Industrial practice shows that when the lubricant content is controlled in the optimal range, the extrusion pressure is stable in the low-fluctuation interval, the production process is smooth, and the extruded blank has uniform density, smooth surface and stable dimensional tolerance, which is suitable for mass production of high-standard PTFE extrusion products PTFE SHEET.

Excessively high lubricant content will also bring adverse effects on extrusion pressure and product quality. Too much lubricant will reduce the effective content of PTFE resin in the unit volume of paste, resulting in excessively low paste viscosity and poor material structural stability. Although the instantaneous extrusion pressure is low, the material is prone to flow disorder and segregation during extrusion, resulting in unstable pressure fluctuation. In addition, excessive lubricant will form a large number of tiny liquid phase gaps inside the extruded blank. After subsequent lubricant volatilization and sintering, these gaps will be converted into internal voids, reducing the density, tensile strength and insulation performance of finished products. Excess lubricant also prolongs the drying and sintering cycle, reducing overall production efficiency.

In actual industrial production, the optimal lubricant content needs to be matched according to product specifications, die size and extrusion speed. Thin-walled precision products require appropriately higher lubricant content to ensure low-pressure stable extrusion and high dimensional accuracy; thick-walled high-strength products need moderate low lubricant content to ensure high resin density and avoid excessive voids after sintering. Real-time monitoring of extrusion pressure changes can also feedback and adjust lubricant ratio dynamically, realizing closed-loop optimization of formula and process. Reasonable control of lubricant content is the key to stabilize extrusion pressure, reduce production costs, and improve the comprehensive performance of PTFE extruded products.