Developing low-voltage heat-resistant wires and cables? At that time, people often get confused about which heat-resistant conductor, insulation material, protective layer structure to choose, as well as the usage environment and methods of heat-resistant wires and cables. This article refers to the opinions of foreign heat-resistant wire and cable experts and provides brief answers to these questions.

Question 1: If the continuous rated temperature of FEP (commonly known as PTFE fluorinated ethylene propylene copolymer) and silicone rubber insulated cables is 200 ℃, what is the difference? Which material is better for the same purpose?

Answer: FEP PTFE is a thermoplastic that melts again when exposed to sufficiently high temperatures. Silicone rubber is a thermosetting material that can form stronger chemical bonds within its molecules under the action of thermally activated catalysts. When exposed to excessively high temperatures, silicone rubber will carbonize or degrade into very fine powders.

This fundamental difference is crucial for deciding whether to apply cable products to ultra-high temperature environments or flame environments. The plastic insulation layer will melt inside the installation pipeline and on the cable tray, and drip onto the structures and equipment below, requiring expensive cleaning or replacement costs. Silicone rubber materials, on the other hand, only carbonize into powder in high temperature or flame environments, making it easy to remove and replace. In addition, PTFE is a material harder than silicone rubber, with an ultimate tensile strength twice that of silicone rubber.

This difference is why a fiber braided layer is added to the surface of silicone rubber insulated wires and cables. Adding a woven layer can improve the cutting resistance and wear resistance of the product.

FEP Teflon is both stiff and hard. The FEP insulation layer has a certain degree of memory, and after the wires and cables are wound on the reel and released, they will maintain their original circular shape when packaged in rolls.

　　 Silicone rubber insulated wire and cableOn the contrary, they are very soft and have no memory of shape, making them very suitable for repeated bending situations.

From the perspective of electrical performance, both materials are excellent electrical insulation materials. FEP Teflon is more suitable for transmitting high-frequency AC signals because it can be extruded into the thinnest insulation thickness, reducing signal path loss, improving transmission speed, and extending transmission distance without the need for amplifiers. On the contrary, silicone rubber insulated wires and cables will retain capacitive charges for a long time.

In terms of moisture resistance, FEP PTFE can prevent moisture. It will not absorb moisture, even if the insulation thickness is thin, moisture will not penetrate into the interior. Silicone rubber, like many electrical insulation materials, absorbs a small amount of moisture and enters the interior of the structure through the insulation layer.

Question 2: If the continuous rated temperature of PFA PTFE and silicone rubber insulated cables is 200 ℃, what is the difference? Which material is better for the same purpose?

Answer: PFA PTFE (tetrafluoroethylene perfluoroalkoxy ethylene ether copolymer, also known as perfluoroalkyl compound, soluble polytetrafluoroethylene) has similar properties to FEP, except that PFA has a rated temperature of 250 ℃. The performance of silicone rubber with a rated temperature of 200 ℃ is similar to that of mixed materials with a rated temperature of 250 ℃.