The Teflon common tube is made by pressing a polytetrafluoroethylene dispersion resin at a normal temperature with an organic solvent as a squeezing agent, and then drying and sintering. According to the size of the pipe diameter, it can be divided into two types: ordinary pipe and micro pipe. Ordinary tube inner diameter > 4mm, micro tube inner diameter ≤ 4mm.
Typical formulations for the production of PTFE tubes:
Dispersed PTFE resin: 100 parts by weight
Squeezing agent: 18~24
PTFE, squeezing agent → mixing → pressing → drying → sintering → cooling → product.
Production process parameters:
Mixing: temperature ≤19 °C, time 10min~20min, mixing at 25 °C ~ 30 °C for more than 24h.
Billet: The compression rate is about 50mm/min and the pressure is 0~3MPa.
Pushing: the temperature of the cavity is 30 °C ~ 50 °C, the die temperature is 50 °C ~ 60 °C, the pushing rate becomes smaller with the increase of the pipe diameter, and accelerates as the wall thickness becomes smaller.
Drying: below 210 °C, 2h~3h
Sintering: batch sintering, heating rate 60 °C / h, 375 °C ± 5 °C for 4h.
Continuous sintering, drying zone 100 °C ~ 250 °C, preheating zone 250 °C ~ 330 °C, sintering zone 380 °C ~ 420 °C, cooling zone less than 300 °C.