Black Semiconductor Crepe Paper

Our Black Semiconductor Crepe Paper is a special crepe paper. Its color is black. The black comes from carbon black added to the paper. The carbon black gives the paper semiconductor properties. The surface resistivity is between 10^5 and 10^9 ohms. What is the use of semiconductor crepe paper? In high-voltage transformers and cables, there is electric field concentration between the conductor and the insulation layer. Where the field is too concentrated, corona discharge can occur. Corona corrodes insulation materials. Over time, it causes breakdown. Our Black Semiconductor Crepe Paper evens out the electric field. It flattens the sharp peaks of the field. This prevents corona. A customer making ultra-high-voltage transformers came to us. Their product voltage rating is 500 kV. The electric field at the coil ends was very concentrated. Before, they used metal foil for shielding. But metal foil is stiff. It was hard to wrap. We recommended our Black Semiconductor Crepe Paper. The carbon black is evenly distributed in the paper fibers. It is soft. It can stretch. It wrapped around the coil ends smoothly. They did an electric field simulation. After using our paper, the maximum field strength dropped by 40%. Now they are our long-term customer.

Carbon black is conductive. But we only add a small amount. So the overall resistivity is neither too high nor too low. It sits right in the semiconductor range. We strictly control the amount of carbon black. We test every batch for surface resistivity. We make sure it stays between 10^5 and 10^9 ohms. This range is recognized by the industry as most effective for corona shielding. Our Black Semiconductor Crepe Paper also has wrinkles. The stretch rate is 20%. It can wrap around irregular surfaces without wrinkling. We test every batch for surface resistivity and breakdown voltage. Breakdown voltage is above 5 kV. Even though it is semiconductor, we still ensure it is at least 3 kV. We also do a carbon black dispersion test. The carbon black must be uniform. No clumps.