Explore Carbon Black Structure and Classification

Carbon Black

Carbon black is an amorphous carbon. It is a light, loose, very fine black powder with a very large surface area ranging from 10 to 3000 m2/g. It is the product of incomplete combustion or thermal decomposition of carbon-containing substances (coal, natural gas, heavy oil, fuel oil, etc.) in the absence of air. Those made from natural gas are called “gas black”, those made from petroleum are called “lamp black”, and those made from acetylene are called “acetylene black”. There are also “pot black”, “furnace black” and “smelter black”. According to the nature of carbon black, there are “enhanced carbon black”, “conductive carbon black”, “wear-resistant carbon black” and so on. Used as a black dye for printing inks, ink, paints, etc.. Also used as reinforcing agent for rubber.

History of Carbon Black

History of Carbon Black Development

According to records, China is one of the first countries in the world to produce carbon black. In ancient times, people burned animal and plant oils, pine branches, and collected the black ash condensed from the fire smoke, which was used to make ink and black pigment. This black ash called “soot” is the earliest carbon black.

In 1821, people in North America for the first time with natural gas as a raw material for the production of carbon black, carbon black is no longer “soot” so simple, it is “gaseous or liquid hydrocarbons in the air under the conditions of incomplete combustion or thermal decomposition of amorphous carbon generated by the decomposition of the loose, lightweight and very fine black powder. It is a loose, light and very fine black powder. Large oil and gas fields were exploited one after another, and the continuous supply of raw materials pushed the production of carbon black from manual operation into the era of large-scale industrialisation.

In 1912, it was discovered that carbon black has a reinforcing effect on rubber, and since then carbon black has gradually become an indispensable raw material for the rubber industry. The world rubber industry raw material consumption ranked first in the raw rubber, the second is carbon black; in other words, carbon black has become the largest consumption of rubber compounds. The consumption of carbon black generally accounts for 40% to 50% of the rubber consumption, that is to say, in the rubber formula, usually every two rubber will be used with the use of a carbon black.

Carbon black structure

The structural nature of carbon black is expressed in terms of the degree to which the particles of carbon black are aggregated into chains or grapes between particles. Carbon black composed of coalescers consisting of the size, morphology and number of particles in each coalescer is called high structural carbon black. Commonly used oil absorption value indicates the structural, the greater the oil absorption value, the higher the structural carbon black, easy to form a spatial network channel, and is not easy to destroy. High-structured carbon black particles fine, network chain stacking close, large specific surface area, more particles per unit mass, is conducive to the formation of chain conductive structure in the polymer, which in the many varieties of carbon black to acetylene carbon black is the best. Wide particle size distribution of carbon black particles than the distribution of narrow carbon black particles can give polymer conductivity, and statistical methods to explain this phenomenon. Wide particle size distribution of carbon black, a small number of large diameter particles need to be a huge number of smaller diameter particles to compensate for the same average particle size distribution of carbon black than the distribution of carbon black has a narrower total number of particles.

Carbon Black Classification

According to the production:

Mainly divided into lamp black, gas black, furnace black and channel black.

According to use:

Carbon blacks are usually divided into pigmented carbon blacks, rubber carbon blacks, conductive carbon blacks and special carbon blacks according to their applications.

Pigmented Carbon Blacks – Internationally, carbon blacks are usually classified into three categories according to their colouring ability, i.e. high pigmented carbon blacks, medium pigmented carbon blacks and low pigmented carbon blacks. This classification is usually indicated by three letters, the first two letters indicate the colouring ability of the carbon black, and the last letter indicates the production method.

Carbon black for rubber – Carbon black for rubber was originally classified according to particle size, but later changed to be classified according to nitrogen surface area. In addition, the naming takes into account factors such as the vulcanisation speed and structure of the carbon black pigment, and consists of 4 systems. The first English letter represents the vulcanisation speed of the rubber, with N representing normal vulcanisation speed and S representing slow vulcanisation speed. The last 3 are Arabic numerals. The first number represents the carbon black nitrogen surface area range, which is listed as 0 to 9 grades. The second and third numbers are designated by the ASTM D24.41 Committee on Carbon Blacks and Terminology, reflecting different degrees of structure, i.e., the approximate high and low structure of the carbon black is determined with a certain degree of arbitrariness. Relatively speaking, the higher the number, the higher the structure.

By Function:

Mainly divided into reinforcing carbon black, colouring carbon black, conductive carbon black and so on.

By model:

Mainly divided into N220, N330, N550, N660, N990, N110, N115, N234, N326, N339, N375, N351, N550 and so on.

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