Basic Knowledge Of Carbon Black

Posted by RachelHJM on May 14th, 2017

1.What is carbon black?

Carbon black is a kind of amorphous carbon. Carbon black generally refers to simple carbon particles. Generally due to inadequate organic combustion, hydrogen and oxygen turn into water, while carbon has inadequate combustion, the molecules will be separated and form carbon black.

Physical properties of carbon black

Carbon black is basically non-toxic, but it easily has flying and pollution, so often it’s used as color masterbatch in the plastics industry. This eliminates pollution as well as improves the dispersion of carbon black in plastic. The main physical form of carbon black is powdery or fluffy, beadlike or granular, and it’s insoluble in water and solvents.

Chemical properties of carbon black

The structural property of the carbon black is expressed as the degree of chain-like or grape-like formation between the carbon black particles, and the pure carbon black chemical formula is C. Carbon black particles have a microcrystalline structure. In carbon black, carbon atoms are arranged in a manner similar to graphite, forming hexagonal planes. Usually 3~5 layers form a microcrystal. Since in each graphite layer of carbon black crystallite, the arrangement of carbon atoms is orderly, while in the adjacent layers, carbon atom arrangement is disordered, it is also known as quasi-graphite crystal.

How to make carbon black?

Ninety-five percent of the carbon black is made by the furnace method. The raw material (petroleum) is injected into a high temperature reactor in which the hydrocarbons are cracked and dehydrogenated to form carbon and graphite-like microstructures. The carbon black is composed of fine primary particles which are fused to form aggregates. Operations after the reactor include granulating "fluffy" low density carbon black to improve storage and handling. Use the special manufacturing techniques which have dispersion, cleanliness, and other target-critical properties and are suitable for improvement to optimize the plastic grade so as to enhance performance of the specific application.

2. Classification and varieties of carbon black

According to the manufacturing methods, carbon black can be divided into carbon black by the contact method, carbon black by the furnace method, carbon black by the new process, carbon black by the thermal cracking method, the spraying method, the channel carbon black. Click the following for details: carbon black manufacturing process.

The carbon black is classified into hard carbon black and soft carbon black by the function; the particle size of the hard carbon black is 40 nm or less, and the soft carbon black has a particle diameter of 40 nm or more.

According to the purpose, carbon black is divided into universal carbon black for rubber, color carbon black and conductive carbon black. According to using performances, carbon black is divided into super wearable carbon black, medium wearable carbon black, superb wearable carbon black, fine particle furnace black, high pressure furnace black, general furnace black, high setting drawing furnace black, semi-reinforcing furnace black, fine-particle thermal cracking carbon black, medium-particle thermal cracking carbon black, channel carbon black that can be mixed easily, channel carbon black that can be mixed.

According to ASTM standard classification, since 1980s, China has used USA ASTM 1765-81 to classify and name carbon black. The nomenclature consists of four digits. The first symbol is N or S on behalf of the curing rate. Wherein N represents the normal vulcanization rate; and S shows that the vulcanization rate is slow. There are three figures after N or S. The first figure shows the average particle size range of carbon black; the second and the third have no specific meaning and represent difference of different brands of various series. Among them, the particle size is divided into 10 ranges according to the data measured by the electron microscope, and the diameter of the carbon black used in the rubber is 11-500nm.