Sintered and expanded polytetrafluoroethylene production comprises extruding raw polytetrafluoroethylene raw material, expanding the extruded material, thermally re-densifying the expanded material and sintering the re-densified material

摘要

The sintered and expanded polytetrafluoroethylene (PTFE) production comprises extruding raw polytetrafluoroethylene raw material, expanding the extruded material for uni-directional alignment of fibers in the material using a strain ratio (1:5-1:7). The expanded material is thermally re-densified using the strain ratio of 1.4:1-3.8:1. The re-densified material is sintered (350[deg]C), and the sintered material has density of 0.5-1.5 g/cm3. The strain ratio is ratio of the material supply rate to the material discharge rate. The sintered and expanded polytetrafluoroethylene production comprises extruding raw polytetrafluoroethylene raw material, expanding the extruded material for uni-directional alignment of fibers in the material using a strain ratio (1:5-1:7). The expanded material is thermally re-densified using the strain ratio of 1.4:1-3.8:1. The re-densified material is sintered (350[deg]C), and the sintered material has density of 0.5-1.5 g/cm3. The strain ratio is a ratio of the material supply rate to the material discharge rate. The material density is minimized in the expansion, and the density is increased in the re-densification. The material expansion and the re-densification are occurred at 100 to 327[deg]C. The raw PTFE material and/or the extrudate are: modified with dyes and/or fillers; and provided with glass beads, powdered glass fibers, silicon oxide, high-grade steel powder or bronze powder. An independent claim is included for an expanded and sintered polytetrafluoroethylene material.