Technical Questions And Answers For Heat Resistant Wire And Cable

- Mar 07, 2018-

In the development of low-voltage heat-resistant wire and cable, usually into the choice of which heat-resistant conductor, insulation materials, protective layer structure and heat-resistant wire and cable use of the environment and methods of confusion. This article refers to foreign heat-resistant wire and cable experts, to do a brief answer to these questions.

Q 1: If FEP (commonly known as Teflon-vinyl fluoride propylene copolymer) and silicone rubber insulated cable, the continuous rated temperature is 200 ℃, then, what is the difference? What kind of material is better for the same purpose?

A: FEP Teflon is a thermoplastic that melts again when exposed to a high enough temperature. and silicone rubber is thermosetting material, under the action of the hot activation catalyst, in its molecule can form stronger chemical bond. When exposed to too high a temperature, silicone rubber will be carbonized or degraded to very fine powder.

This fundamental difference is important for deciding whether to apply a cable product to an extremely hot or flame environment. The plastic insulating layer will melt in the installation pipe and the cable tray, and drop on the structure and equipment below, which will cost a lot of costly cleaning or replacement. The silicone rubber material, in contrast, its high-temperature or flame environment is only carbonation into powder, clear and replacement are very easy. In addition, Teflon is a hard material than silicone rubber, the ultimate resistance to tensile is twice times the silicone rubber.

The difference is why silicone rubber insulated wire and cable surfaces should also be coupled with a fiber braid. Plus woven layer can improve the product's cutting resistance and wear resistance.

FEP Teflon is stiff and stiff. FEP insulating layer has a certain memory, wire and cable around the online disk and then release, will always maintain the original volume packaging when the ring shape.

Silicone rubber insulated wire and cable on the contrary, they are very soft, no memory of the shape, it is suitable for the occasion of repeated bending.

In terms of electrical properties, both of these materials are good electrical insulating materials. FEP Teflon is more suitable for transmission of high-frequency AC signals, because FEP Teflon can squeeze into the thinnest insulation thickness, can reduce signal path loss, improve transmission rate and extend transmission distance, without the need to use amplifier. In contrast, silicone rubber insulated wire and cable will retain the capacitance charge for a long time.

In addition to Moistureproof, FEP Teflon is able to damp-proof. It will not absorb moisture, even if the thickness of the insulation is very thin, water will not penetrate the interior. Silicone rubber, like many electrical insulating materials, absorbs a small amount of water and enters the structure inside through an insulating layer.

Q 2: If the continuous rated temperature of the PFA Teflon and silicone rubber insulated cable is 200 ℃, what is the difference? What kind of material is better for the same purpose?

A: The performance of PFA Teflon (tetrafluoroethylene-vinyl ether copolymer, also known as fluorinated alkyl, soluble PTFE) is similar to that of FEP, except that the nominal temperature of PFA is 250 ℃. The performance of silicone rubber at a nominal temperature of 200 ℃ is similar to that of a mixture of 250 ℃ at rated temperature.