Analysis and development direction of semi-conductive shielding materials for medium and high voltage cables

The misapplication of EVA and white oilAdd a Blog Post Title

Last time we talked about the correct application of carbon black in the semi-conductive shielding material, now we talk about another formula material status and problems for semi-conductive shielding material.

We know that EVA is a duality of a polymer, it can be seen as plastic,also be seen as rubber, it is the best material of fiber, plastic, rubber this three human synthetic materials, then any synthetic material can be filled with oil, and thus in the early development of China's semi-conductive shielding material, I first applied white oil. Truely white oil is mineral oil, also called paraffin oil, it is a mixture of refined liquid hydrocarbons from petroleum, and to dewax, hydrogenation and decolorization to form a colorless, odorless, transparent and anti-oxidant lubricant. White oil contains active functional groups have plasticizing function, it can be soluble with EVA can change the processing fluidity of the polymer, softness. At that time we do not have high VA content EVA, such as 33% VA, if VA is too high, storage, processing is more difficult, Like Dow and other foreign brand they use high content of EVA, they are almost choose 33% EVA.

The real white oil has a wide range of uses, medical, cosmetic, rubber and plastic molding process, etc. The white oil used in our Chinese shielding material industry has deteriorated. Once with foreign competitor, I know that foreign countries do not use liquid white oil, although now the Koreans also began to use, they tested the Chinese 35KV inner and outer shielding material, came to a conclusion: rubbish. Although I know its not my material, but I feel ashamed because he is also our Chinese manufacture.

Later, I learned that they were "innovating", not using real white oil, but using recycled oil. That so-called "white oil" is dark brown, flash point is very low, when they do heat loss test, the whole laboratory is smoke. This so-called "white oil" is corrosive, highly acidic, it not only corrodes their own processing equipment, and even corrode the cable factory extruder, vulcanization tube, thickness gauge (Sikela), and even the cable factory sewage system to work, this is a prominent phenomenon.

We Winpower never use "yellow" fake white oil in our products!

That low-priced so-called white oil, similar to the catering industry in the ban on the use of gutter oil.That is why foreign comptitors call some Chinese semiconductive material is "rubbish", this kind of oil, the flash point is very low, with high acid value.