The origins of insulating paper date back to the late 19th century, during the nascent stages of the electrical industry's development. With the widespread adoption of power systems and electrical equipment, it became evident that reliable insulating materials were essential to prevent current leakage and short circuits between metal coils and equipment components. Early insulating paper was primarily manufactured from cotton or hemp fibers subjected to simple processing, and it was utilized for winding insulation in transformers, generators, and electric motors.
As the demand for high-voltage, high-temperature, and high-performance insulating materials in electrical equipment continued to rise, both the manufacturing processes and constituent materials of insulating paper underwent gradual refinement. Wood pulp fibers progressively replaced hemp and cotton fibers; furthermore, the paper was subjected to processes such as bleaching, pressing, and drying to ensure uniform thickness while significantly enhancing its mechanical strength and electrical insulation properties.
Concurrently, the advent of oil-impregnated insulating paper enabled high-voltage equipment-such as transformers-to operate safely at significantly higher voltage levels.
Driven by the evolution of the electrical industry and the emergence of new energy technologies, insulating paper has continued to advance in terms of both material properties and application domains. New product categories-including high-temperature insulating paper, composite resin insulating paper, and specialty fiber insulating paper-have successively emerged to meet the stringent requirements of the aerospace, new energy power, and high-end electronics sectors regarding lightweight design, heat resistance, and chemical corrosion resistance. The developmental trajectory of insulating paper not only reflects the progress of power technology but has also served to drive innovation in the fields of composite materials and insulation technology.
