Black Semiconductor Grade Crepe Wrapping Paper

Black semiconductor grade crepe wrapping paper is a functional material for high-voltage insulation. Carbon black components are uniformly dispersed within standard crepe insulation paper to deliver semiconductor characteristics with surface resistivity controlled between 10⁵ and 10⁹ ohms. This critical resistivity range avoids full insulation or full conductivity, enabling slow and uniform electric field dissipation. Wrapping coil ends or cable shielding layers with this material flattens concentrated peak electric fields, effectively suppressing corona discharge, protecting primary insulation layers from corona erosion and drastically extending equipment service life. Semiconductor shielding layers become increasingly critical for equipment operating at higher voltage grades.

A manufacturer of extra-high voltage transformers produces 500kV grade equipment with highly concentrated electric fields at coil ends. Their previously used metal foil shielding suffered poor conformability to special-shaped parts due to rigid material, compromising shielding effectiveness. We recommended black semiconductor crepe wrapping paper with evenly dispersed carbon black within paper fibers for flexible, stretchable conformability to end sections. Electric field simulation conducted by the customer demonstrated a 40% reduction in maximum electric field intensity after adopting our paper, delivering remarkable performance improvements. They remain our long-term stable customer. The core technical challenge of black semiconductor grade crepe wrapping paper lies in uniform carbon black dispersion: carbon black agglomeration causes abnormal local resistivity triggering performance failures. We strictly control carbon black ratios and dispersion processes with surface resistivity testing conducted on every batch to maintain consistent values within the standard range.

• Corona shielding of coil ends for high-voltage transformers
• Insulation shielding layers of high-voltage cables
• Corona-resistant layers of high-voltage motor bars
• Electric field equalization shielding for extra-high voltage equipment
• All high-voltage insulation scenarios requiring uniform electric field distribution

We rank among early domestic manufacturers to achieve mass production of semiconductor crepe wrapping paper with years of technical accumulation in carbon black dispersion and papermaking processes. Two core production challenges exist for semiconductor paper: first, uniform dispersion of carbon black into paper pulp without agglomeration to eliminate uneven resistivity; second, precise control of surface resistivity within the narrow 10⁵ to 10⁹ ohms window, where values outside this range compromise functionality. Our technical team finalized stable formulas and processes through repeated iterations delivering consistent batch performance. The factory operates complete production lines for pulping, embossing and slitting with full independent control over all processes from raw material pulping to finished product packaging. Annual production capacity reaches 1,000 tons with monthly capacity of 200 tons to stabilize large order supply. Products are exported to South America, Southeast Asia, the Middle East and other overseas markets with a solid industry reputation in high-voltage transformer sectors.

Quality control standards for semiconductor crepe paper are far stricter than ordinary crepe paper. Beyond routine thickness, tensile strength and breakdown voltage testing, surface resistivity testing is mandatory for every batch via four-point probe multi-point measurement to guarantee uniform roll-wide resistivity falling fully within the standard 10⁵ to 10⁹ ohms range. We also conduct carbon black dispersion testing with microscopic observation of carbon black particle distribution within fibers, rejecting batches with obvious agglomeration outright. Final full visual inspection before delivery eliminates color differences, stains and surface damage. All test data is recorded in physical files accessible to customers upon request for batch-specific test reports. The company holds ISO9001 certification, and products have passed testing by authoritative institutions with all indicators meeting national standards.

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