Heat resistant wire & cable cable technology questions

by:AAA     2020-03-18
When developing low-voltage heat-resistant wires and cables, they are usually confused about which heat-resistant conductor, insulating material, sheath structure and the use environment and method of heat-resistant wires and cables to choose. This article refers to the opinions of foreign heat-resistant wire and cable experts and gives a brief answer to these questions. Q 1: If FEP (Commonly known as Teflon--Fluorinated ethylene propylene copolymer) And the continuous rated temperature of silicone rubber insulated cables is 200 ℃, so, what is the difference? Which material is better for the same purpose? A: FEP Teflon is a thermoplastic that melts again when exposed to a sufficiently high temperature. However, silicone rubber is a thermosetting material, which can form stronger chemical bonds in its molecules under the action of thermal activation catalyst. When exposed to excessive temperatures, silicone rubber will carbonize or degrade into very fine powder. This fundamental difference is very important for deciding whether to apply cable products to ultra-high temperature environment or flame environment. The plastic insulation layer will melt in the installation pipeline and the cable bridge, and drip on the structure and equipment below, which requires expensive cleaning or replacement. And silicone rubber material on the contrary, it is high temperature or flame environment just carbonized into powder, removal and replacement are easy. In addition, Teflon is a harder material than silicone rubber, and its ultimate tensile strength is twice that of silicone rubber. This difference is the reason why a fiber woven layer is added to the surface of silicone rubber insulated wires and cables. Adding woven layer can improve the cutting resistance and wear resistance of the product. FEP Teflon is stiff and hard. The FEP insulation layer has a certain memory. After the wire and cable are wound on the coil and then released, it will always maintain the original circular shape when it is rolled and packaged. On the contrary, silicone rubber insulated wires and cables are very soft and have no memory of shape, which is very suitable for repeated bending occasions. From the electrical performance, these two materials are good electrical insulation materials. FEP Teflon is more suitable for transmitting high-frequency AC signals, because FEP Teflon can be squeezed into the thinnest insulation thickness, which can reduce signal path loss, improve transmission rate and extend transmission distance without using amplifiers. On the contrary, silicone rubber insulated wires and cables will retain capacitive charge for a long time. In addition, FEP Teflon is moisture-proof. It will not absorb moisture, and even if the insulation thickness is very thin, the moisture will not penetrate into the interior. However, silicone rubber, like many Electrical insulating materials, will absorb a small amount of water and enter the interior of the structure through the insulating layer. Question 2: if the continuous rated temperature of PFA Teflon and silicone rubber insulated cable is 200 ℃, what is the difference? Which material is better for the same purpose? A: PFA Teflon (Teflon- Perfluoroalkoxy vinyl ether copolymer, also known as perfluoroalkylates, soluble polytetrafluoroethylene) The performance of is similar to FEP, except that the rated temperature of PFA is 250 ℃. The performance of silicone rubber with a rated temperature of 200 ℃ is similar to that of mixture materials with a rated temperature of 250 ℃.
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