Carbon black

Carbon black is a material produced by the incomplete combustion of heavy petroleum products such as FCC tar, coal tar, ethylene cracking tar, and a small amount from vegetable oil. Carbon black is a form of amorphous carbon that has a high surface area to volume ratio, and as such it is one of the first nanomaterials to find common use, although its surface area to volume ratio is low compared to activated carbon. It is similar to soot but with a much higher surface area to volume ratio. Carbon black is used as a pigment and reinforcement in rubber and plastic products.



Common uses

The most common use [70%] of carbon black is as a pigment and reinforcing phase in automobile tires. Carbon black also helps conduct heat away from the tread and belt area of the tire, reducing thermal damage and increasing tire life. Carbon black particles are also employed in some radar absorbent materials and in printer toner.

Total production is about 8.1 million tonnes (2006) [http://www.carbon-black.org/what_is.html] . About 20% of world production goes into belts, hoses, and other non-tire rubber goods. The balance is mainly used as a pigment in inks, coatings and plastics.

Carbon black from vegetable origin is used as a food coloring, in Europe known as additive E153.

Reinforcing carbon blacks

The highest volume use of carbon black is as a reinforcing filler in rubber products, especially tires. While a pure gum vulcanizate of styrene-butadiene has a tensile strength of no more than 2.5 MPa, and almost nonexistent abrasion resistance, compounding it with 50% of its weight of carbon black improves its tensile strength and wear resistance as shown in the below table.

Practically all rubber products where tensile and abrasion wear properties are crucial use carbon black, so they are black in color. Where physical properties are important but colors other than black are desired, such as white tennis shoes, precipitated or fused silica is a decent competitor to carbon black in reinforcing ability. Silica-based fillers are also gaining market share in automotive tires because they provide better trade-off for fuel efficiency and wet handling due to a lower rolling loss compared to carbon black-filled tires. Traditionally silica fillers had worse abrasion wear properties, but the technology has gradually improved to where they can match carbon black abrasion performance.

Pigment

Carbon black (Colour Index International, PBL-7) is the name of a common black pigment, traditionally produced from charring organic materials such as wood or bone. It consists of pure elemental carbon, and it appears black because it reflects almost no light in the visible part of the spectrum. It is known by a variety of names, each of which reflects a traditional method for producing carbon black:
* Ivory black was traditionally produced by charring ivory or bones (see bone char).
* Vine black was traditionally produced by charring desiccated grape vines and stems.
* Lamp black was traditionally produced by collecting soot, also known as lampblack, from oil lamps.

Newer methods of producing carbon black have superseded these traditional sources, although some materials are still produced using traditional methods. For artisanal purposes, it is very useful.

Cabonblack Grade

Grade	Description/Uses
N-234	Fine active carbon black with increased structure. Provides high wear resistance and high level of reinforcement of different rubbers. Rubbers, containing N-234, are characterized by high modulus and good smoth extrusion of raw compound. Car tyre treads with high performance, retreading. High quality industrial rubber goods and conveyor belts.
N-220	Fine active carbon black. Imparts to rubber high wear resistance and tear strength, relatively low modulus. Tyre tread, retreading. High-quality industrial rubber goods and high grade conveyor belts.
N-375	Fine active carbon black. Provide high breaking and wear resistance. Improved ability of process. Tyre treads, retreading. Industrial rubber goods and conveyor belts.
N-339	Fine active carbon black with increased strucure. Imparts high modulus, improved extrusion, wear resistance and hysteresis N-330. Tyre treads, retreading. Industrial rubber goods and conveyor belts.
N-330	Fine active carbon black. Provides high stensile strength and good wear resistance. Tyre breaker and sidewalls. Solid tyres, agrucultural tyres, sleeve, conveyor belts, industrial rubber goods, fan-belt.
N-326	Fine low-structure active carbon black. Gives low modulus, high elongation at break, high tear and fatigue strength. Compundus for tyre breaker, including breaker for solid and off-road tyres.
N-550	Medium-dispersion, medium-active carbon black. Imparts high extrudability, relatively high tear resistance. Compounds for tyre carcass and tube. Profile-extruded goods. Industrial rubber good, seal, hoses.
N-539	Similar to N-550 it is medium-dispersion, medium-active carbon black. Provides improved processing properties, possible increased loading. Compounds for tyre carcass and tube. Profile-extruded goods. Industrial rubber good, seal, hoses. One-layer roofing system.
N-660	Medium-dispersion, medium-active, low-structure carbon black. Provides higher die-swell, high resilience at relatively high hardness. May be incorporated in large quantity. Compounds for tyre carcass and tube. Moulded goods, goods extrusion. Industrial rubber goods, sleeves. One-layer roofing system. Isolating cable rubbers.