Carbon Black

Carbon black is a nanostructured material of the carbon family, produced by the incomplete combustion of hydrocarbons under controlled conditions. It has two main industrial functions: to reinforce rubber and plastic compounds, and to act as a pigment that provides deep black color and UV protection.

What the grade codes tell you

Under ASTM D1765, a grade code consists of the letter N and three digits. The letter N stands for "normal cure rate". The first digit indicates the average particle size range: a lower digit means smaller particles, higher surface area and stronger reinforcement. The last two digits are a serial number that distinguishes structure and other properties.

In practice, the N100–N300 series are hard grades: they deliver high abrasion resistance and high reinforcement and are used in tire treads. The N500–N700 series are soft grades: they offer lower reinforcement, easier processing and lower heat build-up, and are preferred in carcass, hose, profile and masterbatch applications.

Four main uses

• Filler and reinforcing agent in rubber: Tires (inner liner, carcass, sidewall, tread) and molded and extruded industrial rubber goods — belts, hoses, seals, diaphragms, vibration mounts, bushings, air springs, chassis bumpers, pads, boots, wiper blades, conveyor wheels and rollers.
• UV protection: Prevents plastics from aging under ultraviolet light; used in conductive packaging, moldings, pipes and semiconductive cable compounds.
• Pigment for printing inks and paints: Color matching and pigmentation in automotive (primer and clear coats), marine, aerospace, decorative, wood and industrial coatings.
• Electrical conductivity: Makes insulating polymers such as plastics conductive; used in electronic packaging, safety applications and automotive parts.

Which grade should I choose?

The choice starts with three questions: Will the product wear? (if yes, a hard grade), Will it flex continuously? (if yes, low hysteresis), Are color and UV protection the priority? (if yes, a soft grade is enough). Our comparison table shows the technical values of all grades side by side; if you are undecided, our technical team will work with you to find the grade that fits your formulation.