PTFE tube which has pressed molding process, extrusion, hydraulic method, welding method, winding method, etc., which pushed the main method. Usually decentralized PTFE resin, particle diameter 500 m, an apparent density of 0.45g / ml ~ 0.55g / ml. Small diameter pipe resin selected compression large, medium and large diameter pipe is relatively small selection of compressed resin. Extrusion aid is usually chosen No. 200 and No. 260 solvent oil. PTFE pipe for secondary processing can be obtained PTFE heat shrink tubing, PTFE spiral, PTFE wire reinforced hydraulic tubes.
1.1, PTFE Teflon tube ordinary pipe is ordinary dispersion PTFE resin at room temperature in an organic solvent extrusion aid was pressing push, and then by drying, sintering. Press the diameter size can be divided into two kinds of common micro-tube and tube. Common tube diameter> 4mm, miniature tube diameter ≤4mm.
PTFE tube produced typical formula:
PTFE resin dispersion: 100 (parts by weight)
Extrusion aid: 18 to 24
PTFE, extrusion aid mixture → → → pressing → cooling → drying → sintering products.
Production process parameters:
Mixed: Temperature ≤19 ℃, time 10min ~ 20min, mixing completed at 25 ℃ ~ 30 ℃ parking for more than 24h.
Billet: Compression rate of about 50mm / min, pressure of 0 ~ 3MPa.
Pressing: feed chamber temperature is 30 ℃ ~ 50 ℃, the die temperature is 50 ℃ ~ 60 ℃, pushing the rate increases with the diameter becomes smaller as the wall thickness becomes smaller accelerated.
Drying: below 210 ℃, 2h ~ 3h
Sintering: Intermittent firing, heating rate 60 ℃ / h, 375 ℃ ± 5 ℃ heat 4h.
Continuous sintering, drying zone 100 ℃ ~ 250 ℃, a preheating zone 250 ℃ ~ 330 ℃, the sintering zone 380 ℃ ~ 420 ℃, the cooling zone less than 300 ℃.
Major equipment: mixer, pre-molding machine, vertical push presses, drying and sintering furnace.