Full definition
Carbon black is a finely divided elemental carbon produced primarily through the incomplete combustion or thermal decomposition of heavy petroleum oils. This material serves as the most important reinforcing filler in the rubber industry, significantly enhancing the physical properties of rubber compounds. When added at a concentration of 30-80 parts per hundred rubber (phr), carbon black can dramatically increase its tensile strength by 2-5 times, improve abrasion resistance by 5-10 times, and enhance tear resistance and UV protection. The incorporation of carbon black not only improves performance but also optimizes the longevity and durability of rubber products, which is essential for various industrial applications.
Carbon black is classified according to ASTM D1765 by its particle size (surface area) and structure (aggregate complexity). The grades range from N110-N121, known as Super Abrasion Furnace (SAF) blacks, with a particle size of 15-20 nm, providing maximum reinforcement for tire treads, to N762-N990 thermal blacks, which are 100-500 nm in size and are used primarily for cost reduction with minimal reinforcement. Other notable grades include N220-N234 (Intermediate Super Abrasion Furnace, ISAF, 20-25 nm) suitable for belt covers, and N330 (High Abrasion Furnace, HAF, 28-36 nm), which is the most widely used general-purpose grade. Understanding these grades allows manufacturers to select the appropriate carbon black for specific applications.
Key properties of carbon black include the iodine adsorption number, which indicates its surface area (measured according to ASTM D1510), DBP absorption, which assesses its structure (measured per ASTM D2414), and tint strength, which evaluates color performance. With global production exceeding 15 million tonnes annually, the tire industry accounts for over 70% of carbon black consumption, making it a critical material for enhancing the performance of tires and other rubber products. Major producers of carbon black include Birla Carbon, Cabot, Orion, and Tokai, which together contribute to the global supply of this essential material.