The history of carbon black development and its classification

A black powdery substance in which hydrocarbons are incompletely combusted or pyrolyzed by a gas phase under strictly controlled process conditions. Its composition is mainly elemental carbon and contains a small amount of oxygen, hydrogen and sulfur. The carbon black particles are approximately spherical and have a particle size of between 10 and 500 μm. Many particles often fuse or coalesce into three-dimensional bond-like or fibrous aggregates. In rubber processing, rubber is added to the rubber as a reinforcing agent (see reinforcing material) and filler.

Carbon black is one of the oldest industrial products. As early as BC, China used vegetable oils to burn incompletely to produce pigment carbon black. In 1872, the United States first produced carbon black by tank method using natural gas as a raw material. At the time, carbon black was still mainly used as a coloring agent. After S.C. Mott discovered the reinforcing effect of carbon black on rubber in 1912, the carbon black industry developed rapidly. In the 1920s, gas black and thermal cracking black, which were based on natural gas, appeared. R.D. Snow began researching efficient carbon black production methods in 1937. Later, J.C. Craig worked on the production of carbon black from liquid hydrocarbons and developed the oil furnace process. In 1941, the first batch of oil furnace black was produced. In 1943, the world's first industrial-scale oil furnace black factory was put into production in the United States. Today, the oil furnace method is the most efficient and economically efficient carbon black production method. The output of oil furnace black has accounted for 70% to 90% of the total carbon black.

The classification of various carbon blacks by carbon black manufacturers often involves their production methods, such as channel black, furnace black and thermal cracking black. It can also be classified according to the purpose, such as carbon black for rubber and carbon black for coloring. The naming principle of carbon black varieties is gradually formed during production and use. Initially, it is represented by the abbreviated letters of the English words of carbon black characteristics and production methods, such as HAF for high wear-resistant furnace black and MCC for medium pigment bath black. The American Society for Testing and Materials (ASTM) has issued a naming system that primarily stipulates the nomenclature of carbon black for rubber. At present, the ASTM naming system has been accepted by all countries in the world. It consists of a letter and three digits. The letter indicates the effect of the surface properties of the carbon black on the rubber processing process. The N indicates a normal vulcanized variety, and the S indicates a slowly vulcanized variety. The first number after the letter indicates the particle size of the carbon black. Based on the average particle diameter measured by electron microscopy, the particle size range of all carbon blacks was divided into 10 grades, the finest is 0 and the thickest is 9. The remaining two numbers are used to distinguish the difference in carbon black structure and performance. For example, the super wear-resistant furnace black can be expressed as SAF or N110; the high wear-resistant furnace black is represented as HAF or N330; the high wear-resistant high-structure furnace black is represented as HAF-HS or N347; the semi-reinforcing furnace black is SRF or N770. The easy mixing tank black is expressed as EDC or S300.