Vulcanized fibre and fish paper are versatile engineering materials that are used in many mechanical and electrical applications. They are made by soaking cotton rags or fibers in a solution of zinc chloride, which turns the material into a gelatinous mass. After the zinc chloride is washed away, the fibers are dried, heated, and compressed. Vulcanized fiber and fish paper are very tough and provide high dielectric strength. They can be used over a wider range of temperatures than many engineering plastics, but may swell or curl if moisture is absorbed. Typically, however, water-resistant grades and coatings are used to prevent this problem. Vulcanized fibre and fishpaper is also valued for its arc tracking resistance and arch quenching properties. Consequently, electrical grades of these engineering materials are used in devices such as circuit breakers and fuse tubes.
Grades of Vulcanized Fibre and Fish Paper
There are many different grades of vulcanized fibre and fish paper. The main types are commercial grade, bone grade (mechanical grade) and fish paper (electrical grade). Commercial grade products are designed for general-purpose applications. They provide good mechanical and good electrical properties. Bone grade vulcanized fiber and fish paper is very hard and wear resistant, features that make it suitable for mechanical applications. Electrical grade products (fish paper) are engineering to provide the best dielectric or electrical-insulation properties. Electrical fishpaper is available in thinner gages and is more heat-resistant than many plastic materials. Other types of vulcanized fibre and fishpaper are designated as UL 94 and ASTM D-635 compliant, hermetic, hybrid, laminated, and water-resistant. UL 94 and ASTM D-635 products are flame retardant.
Product specifications for vulcanized fibre and fish paper include shape or form, size or dimensions, mechanical properties, electrical properties, thermal properties, and physical properties. Choices for shape or form include bar stock, fabricated or custom shape, rod stock, sheet and board, tube stock, and specialty. Width, thickness, and length are important dimensional specifications to consider. Vulcanized fiber and fish paper differ in terms of mechanical properties such as tensile strength and tensile modulus, and electrical properties such as dielectric strength and arc resistance. Heat resistance and coefficient of thermal expansion (CTE) are important thermal properties. Vulcanized fibre and fish paper also carries specifications for physical properties such as density and water absorption.