According to the characteristics of the use of PTFE Teflon hose, it passes through various liquids, gases or fuels with a certain pressure and is mostly in a bent state. Therefore, the inner tube in the Teflon hose must have low permeability and High bending life is just right. This requires that the pore content in the inner tube of PTFE Teflon resin after sintering should be as small as possible. The only way to increase the cohesive force between resin particles can be to reduce the molecular weight of Teflon to reduce the melt viscosity, but reducing the molecular weight will lead to The increase in crystallinity is not conducive to the improvement of bending life.

In order to solve the contradictory problems at the same time, the Teflon resin must be modified by copolymerization, that is, a small amount of another fluorine-containing monomer such as perfluoropropyl vinyl ether (PPVE) and tetrafluoroethylene (TFE) must be used. In copolymerization, the perfluoroether is used as the side chain of the molecule to hang beside the main chain. Such copolymer not only reduces the molecular weight, but also a small amount of comonomer disturbs the crystallinity of the PTFE main chain and increases its amorphous phase. Although its bending mode decreases, its bending life is increased due to the presence of amorphous phase. In addition, the lower melt viscosity improves the cohesive force between the resin particles and can basically achieve a void-free state.

The hose that transports jet hydrocarbon fuel at high speed will accumulate static charge in the Teflon tube due to friction. In the case of hypoxia, static charge discharge will produce pinholes in the wall of the Teflon PTFE inner tube and leak fluid; when there is oxygen, static charge discharge is the source of fire, so the generated static charge must be disposed of in time. One of the methods is that the Teflon inner tube consists of two layers, that is, most of the tube wall is pure Teflon PTFE and the inner layer in contact with the fluid is an antistatic layer composed of conductive carbon black and Teflon (carbon black The content is about 1%~2%). With this layer of carbon black filled PTFE, once the static charge accumulated can pass through the metal and then be discharged from the surface. The preform of this Teflon PTFE two-color tube is made through a special parting mold.