Carbon Black types and grades

The four production processes yield different types and grades of carbon black products, with the furnace process being of the most versatile. Average particle size, particle distribution, specific surface activity and purity, the degree of homogeneity and the degree of particle aggregation determine the characteristics of carbon black and are primary determinants of its properties. A finer particle size, and therefore a higher surface area, will increase blackness, tint, UV protection, electrical conductivity and viscosity, while lowering dispersibility. Particle distribution impacts rheological properties (the flow / deformation mechanics of a material) as well as plasticizing power. Specific surface activity and purity impact the filling and reinforcing properties, as well as deterministic mine compatibility and reactivity with other substances. Aggregation, or structuring, refers to the way in which the carbon particles are permanently fused together in a random branching structure, or chain, and impacts rheology reinforcement as well as light scattering properties. The table below provides on overview of the products from the four production processes.

Process

Particle Size (nm)

Particle Aggregation

Particle Distribution

Specific Surface

Main Application Segment(s)

Furnace Black

10-80

Variable

Variable

Variable

Specialty Carbon Black & Rubber Carbon Black

Gas Black

10-30

Low

Narrow

High

Specialty Carbon Black

Lamp Black

60-200

Substantial

Broad

Low

Specialty Carbon Black & Rubber Carbon Black

Thermal Black

100-500

Very low

Low

Low

Specialty Carbon Black & Rubber Carbon Black

The properties of most Carbon Black grades are determined by industry-wide standards which have been developed by the German Institute for Standardization (DIN), the International Organization for Standardization (ISO) and the American Society for Testing and Materials (ASTM), with the latter being the most widely used, especially for Rubber Carbon Black grades. These standards are not only used as a measure by which types of Carbon Black are characterized but also as a quality assurance tool for the production process.

ASTM rubber grades can be divided into two basic categories: highly-reinforcing grades and semi-reinforcing grades. Highly - reinforcing grades are identified by ASTM numbers in the 100, 200 and 300 series. These materials are used in tire treads and mechanical rubber goods applications, where they offer good abrasion resistance which is directly related to tread wear. Semi-reinforcing grades are identified by ASTM numbers in the 500, 600 and 700 series. Semi-reinforcing Carbon Black is used in rubber components requiring low heat build-up during dynamic stress.