Paste Extrusion Parameters for High-Strength PTFE Tubing

High-strength PTFE tubing is widely used in high-pressure fluid transmission, chemical pipeline transportation, high-voltage electrical insulation and mechanical protection fields, which puts forward extremely high requirements on tensile strength, compressive resistance, structural compactness and dimensional stability of products. Different from ordinary common PTFE tubes, high-strength PTFE tubing relies on precise matching of paste extrusion process parameters to realize compact internal structure, uniform particle orientation and low void rate, so as to obtain excellent mechanical strength and long-term service reliability. The core extrusion parameters including lubricant ratio, ram speed, extrusion pressure, preheating temperature and die temperature directly determine the final strength performance of PTFE tubing PTFE SHEET.

Lubricant content control is the primary parameter for producing high-strength PTFE tubing. Compared with ordinary products, high-strength tubing needs to reduce the lubricant dosage appropriately on the premise of ensuring smooth extrusion. Moderate low lubricant ratio can improve the resin density of extruded blanks, reduce the residual voids after lubricant volatilization, and enhance the structural compactness of finished products. Excess lubricant will inevitably form micro-pores inside the tube wall after sintering, which become stress concentration points and reduce the tensile and compressive strength of the tubing. At the same time, uniform lubricant dispersion treatment is required in the batching stage to avoid local excessive or insufficient lubrication, ensuring consistent structural density of the entire tube wall PTFE TUBE.

Stable extrusion pressure and constant ram speed are the core dynamic parameters for high-strength tubing molding. High-strength PTFE tubing requires continuous and uniform low-fluctuation extrusion pressure to ensure full rearrangement and tight stacking of PTFE particles. Variable pressure and unstable ram speed will lead to inconsistent particle orientation and uneven density distribution inside the tube wall, resulting in local strength difference and easy fracture under external force. Industrial high-strength tube production adopts constant-pressure and constant-speed extrusion mode, with low-speed stable extrusion in the molding stage to eliminate flow turbulence and ensure axial uniform orientation of PTFE molecular chains, which significantly improves the axial tensile strength and fatigue resistance of the tubing.

Temperature parameters including paste preheating temperature and die temperature also play a key role in strength performance control. Appropriate preheating treatment can homogenize the viscosity of PTFE paste, eliminate internal temperature difference and flow difference, and avoid partial structural defects. Die temperature is strictly controlled within a stable range to ensure that the lubricant does not volatilize in advance during extrusion and the material flows stably. Too high die temperature will cause local lubricant loss, increased friction and surface defects; too low temperature will lead to high paste viscosity, insufficient particle stacking density and reduced structural strength. Stable temperature environment ensures the consistency of physical state of the material during the whole extrusion process.

In addition, post-extrusion traction parameters and blank maintenance process are auxiliary key parameters for high-strength tubing production. Reasonable low-tension uniform traction avoids tensile deformation and internal stress of the tube blank, maintaining the compact structure formed by extrusion. Sufficient static maintenance before sintering enables PTFE particles to further stabilize the stacking state and release residual extrusion stress, which is conducive to improving the structural uniformity and mechanical stability after sintering. Scientific combination and precise control of all extrusion parameters can effectively reduce the void rate of PTFE tubing, improve molecular orientation uniformity, and produce high-strength PTFE tubing with excellent mechanical properties and long-term structural stability.