Carbon black is a material produced by the incomplete
combustionCombustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames, appearance of light flickering.Direct combustion by atmospheric oxygen is a reaction...
of heavy
petroleumPetroleum or crude oil is a naturally occurring, flammable liquid found in rock formations in the Earth consisting of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds.The term "petroleum" was first used in the treatise De Natura Fossilium, published in...
products such as
FCCFluid catalytic cracking is the most important conversion process used in petroleum refineries. It is widely used to convert the high-boiling, high-molecular weight hydrocarbon fractions of petroleum crude oils to more valuable gasoline, olefinic gases and other products...
tar,
coal tarCoal tar is a brown or black liquid of high viscosity, which smells of naphthalene and aromatic hydrocarbons. Coal tar is among the by-products when coal is...
, ethylene cracking tar, and a small amount from
vegetable oilVegetable fats and oils are lipid materials derived from plants. Physically, oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides, as contrasted with waxes which lack glycerin in their structure...
. Carbon black is a form of
amorphous carbonAmorphous carbon or free, reactive carbon, is an allotrope of carbon that does not have any crystalline structure. As with all glassy materials, some short-range order can be observed...
that has a high
surface area to volume ratioThe surface-area-to-volume ratio also called the surface-to-volume ratio and variously denoted sa/vol or SA:V, is the amount of surface area per unit volume of an object or collection of objects. The surface area to volume ratio is measured in units of inverse distance...
, although its surface area to volume ratio is low compared to
activated carbonActivated carbon, also called activated charcoal or activated coal, is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions....
. It is dissimilar to
sootSoot is a general term that refers to impure carbon particles resulting from the incomplete combustion of a hydrocarbon. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolyzed fuel particles such as cenospheres,...
because of its much higher surface area to volume ratio and significantly less (negligible and non-bioavailable) PAH content.
Carbon black is a material produced by the incomplete
combustionCombustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames, appearance of light flickering.Direct combustion by atmospheric oxygen is a reaction...
of heavy
petroleumPetroleum or crude oil is a naturally occurring, flammable liquid found in rock formations in the Earth consisting of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds.The term "petroleum" was first used in the treatise De Natura Fossilium, published in...
products such as
FCCFluid catalytic cracking is the most important conversion process used in petroleum refineries. It is widely used to convert the high-boiling, high-molecular weight hydrocarbon fractions of petroleum crude oils to more valuable gasoline, olefinic gases and other products...
tar,
coal tarCoal tar is a brown or black liquid of high viscosity, which smells of naphthalene and aromatic hydrocarbons. Coal tar is among the by-products when coal is...
, ethylene cracking tar, and a small amount from
vegetable oilVegetable fats and oils are lipid materials derived from plants. Physically, oils are liquid at room temperature, and fats are solid. Chemically, both fats and oils are composed of triglycerides, as contrasted with waxes which lack glycerin in their structure...
. Carbon black is a form of
amorphous carbonAmorphous carbon or free, reactive carbon, is an allotrope of carbon that does not have any crystalline structure. As with all glassy materials, some short-range order can be observed...
that has a high
surface area to volume ratioThe surface-area-to-volume ratio also called the surface-to-volume ratio and variously denoted sa/vol or SA:V, is the amount of surface area per unit volume of an object or collection of objects. The surface area to volume ratio is measured in units of inverse distance...
, although its surface area to volume ratio is low compared to
activated carbonActivated carbon, also called activated charcoal or activated coal, is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions....
. It is dissimilar to
sootSoot is a general term that refers to impure carbon particles resulting from the incomplete combustion of a hydrocarbon. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolyzed fuel particles such as cenospheres,...
because of its much higher surface area to volume ratio and significantly less (negligible and non-bioavailable) PAH content. Carbon black is used as a
pigmentA pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
and reinforcement in
rubberNatural rubber is an elastomer that was originally derived from a milky colloidal suspension, or latex, found in the sap of some plants. The purified form of natural rubber is the chemical polyisoprene, which can also be produced synthetically...
and
plasticPlastic is the general common term for a wide range of synthetic or semisynthetic organic amorphous solid materials suitable for the manufacture of industrial products...
products.
The current
International Agency for Research on CancerThe International Agency for Research on Cancer is an intergovernmental agency forming part of the World Health Organisation of the United Nations....
(IARC) evaluation is that, "Carbon black is possibly
carcinogenA carcinogen is any substance, radionuclide or radiation that is an agent directly involved in the promotion of cancer or in the increase of its propagation. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
ic to
humanHumans are bipedal primates belonging to the species Homo sapiens in Hominidae, the great ape family. They are the only surviving member of the genus Homo. Humans have a highly developed brain, capable of abstract reasoning, language, introspection, and problem solving...
s (
Group 2B)". Short-term exposure to high concentrations of carbon black
dustDust is a general name for minute solid particles with diameters less than 20 thou . Particles in the atmosphere arise from various sources such as soil dust lifted up by wind, volcanic eruptions, and pollution...
may produce discomfort to the
upper respiratory tractThe upper respiratory tract refers to the following parts of the respiratory system:* nose and paranasal sinuses* oral cavity * throat**pharynx*** genioglossus *** hyoid muscles**larynx**trachea...
, through mechanical irritation.
Common uses
The most common use [70%] of carbon black is as a
pigmentA pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
and reinforcing phase in
automobileAn automobile, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...
tires. Carbon black also helps
conductIn heat transfer, conduction is the transfer of thermal energy between neighboring molecules in a substance due to a temperature gradient. It always takes place from a region of higher temperature to a region of lower temperature, and acts to equalize temperature differences. Conduction takes...
heatIn physics and thermodynamics, heat is the process of energy transfer from one body or system due to thermal contact, which in turn is defined as an energy transfer to a body in any other way than due to work performed on the body....
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 materialRadar absorbent material, or RAM, is a class of materials used in stealth technology to disguise a vehicle or structure from radar detection. A material's absorbency at a given frequency of radar wave depends upon its composition...
s and in
photocopierA photocopier is a machine that makes paper copies of documents and other visual images quickly and cheaply. Most current photocopiers use a technology called xerography, a dry process using heat...
and
laser printerA laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers , laser printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced...
tonerToner is a powder used in laser printers and photocopiers to form the printed text and images on the paper. In its early form it was simply carbon powder. Then, to improve the quality of the printout, the carbon was melt-mixed with a polymer...
.
Total production was around in 2006. About 20% of world production goes into
beltsA belt is a looped strip of flexible material, used to mechanically link two or more rotating shafts. They may be used as a source of motion, to efficiently transmit power, or to track relative movement. Belts are looped over pulleys...
,
hoseA hose is a hollow tube designed to carry fluids from one location to another. Hoses are also sometimes called pipes , or more generally tubing...
s, and other non-tire
rubberNatural rubber is an elastomer that was originally derived from a milky colloidal suspension, or latex, found in the sap of some plants. The purified form of natural rubber is the chemical polyisoprene, which can also be produced synthetically...
goods. The balance is mainly used as a pigment in
inkAn ink is a liquid containing various pigments and/or dyes used for coloring a surface to produce an image, text, or design. Ink is used for drawing and/or writing with a pen, brush or quill...
s,
coatingCoating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance...
s and
plasticPlastic is the general common term for a wide range of synthetic or semisynthetic organic amorphous solid materials suitable for the manufacture of industrial products...
s. For example, it is
addedUV light stabilizers are used frequently in plastics, including cosmetics and films. The primary function is to protect the substance from the long-term degradation effects from light, most frequently ultraviolet light...
to
polypropylenePolypropylene or polypropene is a thermoplastic polymer, made by the chemical industry and used in a wide variety of applications, including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and...
because it absorbs
ultravioletUltraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
radiation, which causes the material to
degradeMany natural and synthetic polymers are attacked by ultra-violet radiation and products made using these materials may crack or disintegrate . The problem is known as UV degradation, and is a common problem in products exposed to sunlight...
.
Carbon black from
vegetableA vegetable is an edible plant or part of a plant. However, the word is not scientific, and its meaning is largely based on culinary and cultural tradition. Therefore the application of the word is somewhat arbitrary and subjective. For example, some people consider mushrooms to be vegetables,...
origin is used as a
food coloringFood coloring is any substance that is added to food or drink to change its color. Food coloring is used both in commercial food production and in domestic cooking...
, in
EuropeEurope is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally divided from Asia to its east by the water divide of the Ural Mountains, the Ural River, the Caspian Sea, the Caucasus Mountains , and the Black Sea to the southeast...
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-butadieneStyrene-Butadiene or Styrene-Butadiene-Rubber is a synthetic rubber copolymer consisting of styrene and butadiene. It has good abrasion resistance and good aging stability when protected by additives, and is widely used in car tires, where it is blended with natural rubber...
has a
tensile strengthTensile strength is indicated by the maxima of a stress-strain curve and, in general, indicates when necking will occur. As it is an intensive property, its value does not depend on the size of the test specimen...
of no more than 2.5
MPa-Transportation:* Maritime patrol aircraft, like Nimrod, P-3 Orion* Maritime and Port Authority of Singapore* Maryland and Pennsylvania Railroad* Mauritius Ports Authority* Mount Pleasant Airport, Falkland Islands* Myanmar Port Authority-Academic Degrees:...
, and almost nonexistent
abrasionIn dermatology, an abrasion is a wound caused by superficial damage to the skin, no deeper than the epidermis. It is less severe than a laceration, and bleeding, if present, is minimal. Mild abrasions, also known as grazes or scrapes, do not scar or bleed, but deep abrasions may lead to the...
resistance, compounding it with 50% of its
weightIn the physical sciences, the weight of an object is the magnitude, W, of the force that must be applied to an object in order to support it in a gravitational field. The weight of an object in static equilibrium equals the magnitude of the gravitational force acting on the object, less the effect...
of carbon black improves its tensile strength and wear resistance as shown in the below table.
Types of carbon black used in tires
| Name |
Abbrev. |
ASTM
Desig. |
Particle
Size
nm |
Tensile
Strength
MPa |
Relative
Laboratory
Abrasion |
Relative
Roadwear
Abrasion |
| Super Abrasion Furnace |
SAF |
N110 |
20-25 |
25.2 |
1.35 |
1.25 |
| Intermediate SAF |
ISAF |
N220 |
24-33 |
23.1 |
1.25 |
1.15 |
| High Abrasion Furnace |
HAF |
N330 |
28-36 |
22.4 |
1.00 |
1.00 |
| Easy Processing Channel |
EPC |
N300 |
30-35 |
21.7 |
0.80 |
0.90 |
| Fast Extruding Furnace |
FEF |
N550 |
39-55 |
18.2 |
0.64 |
0.72 |
| High Modulus Furnace |
HMF |
N683 |
49-73 |
16.1 |
0.56 |
0.66 |
| Semi-Reinforcing Furnace |
SRF |
N770 |
70-96 |
14.7 |
0.48 |
0.60 |
| Fine Thermal |
FT |
N880 |
180-200 |
12.6 |
0.22 |
-- |
| Medium Thermal |
MT |
N990 |
250-350 |
9.8 |
0.18 |
-- |
Practically all rubber products where tensile and abrasion wear properties are crucial use carbon black, so they are black in
colorColor or colour is the visual perceptual property corresponding in humans to the categories called red, yellow, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...
. Where physical properties are important but colors other than black are desired, such as white tennis shoes, precipitated or
fumed silicaFumed silica, also known as pyrogenic silica, is a non-crystalline, fine-grain, less-density and much-surface area silica. Not to be confused with silica fume, also known as microsilica.-Properties:...
is a decent competitor to carbon black in reinforcing ability.
SilicaThe chemical compound silicon dioxide, also known as silica , is an oxide of silicon with a chemical formula of ' and has been known for its hardness since antiquity. Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms...
-based
fillersFillers are particles added to material to lower the consumption of more expensive binder material or to better some properties of the mixtured material. Worldwide more than 50 million tons of fillers with a total sum of ca...
are also gaining market share in automotive tires because they provide better trade-off for
fuel efficiencyFuel efficiency, is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance...
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
technologyTechnology is a broad concept that deals with human as well as other animal species' usage and knowledge of tools and crafts, and how it affects a species' ability to control and adapt to its environment...
has gradually improved to where they can match carbon black abrasion performance.
Pigment
Carbon black (
Colour Index InternationalColour Index International is a reference database jointly maintained by the Society of Dyers and Colourists and the American Association of Textile Chemists and Colorists. It was first printed in 1925 but is now published exclusively on the web...
, PBL-7) is the name of a common black pigment, traditionally produced from charring organic materials such as
woodWood is an organic material; in the strict sense wood is produced as secondary xylem in the stems of trees . In a living tree it transfers water and nutrients to the leaves and other growing tissues, and has a support function, enabling woody plants to reach large sizes or to stand up for themselves...
or
boneBones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
. It consists of pure
elementalA chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. The term is also used to refer to a pure chemical substance composed of atoms with the same number of protons.Common examples of elements...
carbonCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
, and it appears black because it reflects almost no
lightLight is electromagnetic radiation, particularly radiation of a wavelength that is visible to the human eye ....
in the visible part of the
spectrumA spectrum is a condition that is not limited to a specific set of values but can vary infinitely within a continuum. The word saw its first scientific use within the field of optics to describe the rainbow of colors in visible light when separated using a prism; it has since been applied by...
. 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
Ivory is formed from dentine and constitutes the bulk of the teeth and tusks of animals such as the elephant, hippopotamus, walrus, mammoth and narwhal....
or bones (see bone charBone char, also known as bone black, ivory black, animal charcoal, or abaiser, is a granular material produced by charring animal bones: the bones are heated to high temperatures in an oxygen-depleted atmosphere to control the quality of the product as related to its adsorption capacity for...
).
- Vine black was traditionally produced by charring desiccated grape
A grape is the non-climacteric fruit, botanically a true berry, that grows on the perennial and deciduous woody vines of the genus Vitis. Grapes can be eaten raw or used for making jam, juice, jelly, vinegar, wine, grape seed extracts, raisins, and grape seed oil...
vineThe term vine may refer to a climbing or trailing plant. The word, derived from Latin vīnea, in the original sense referred to the grapevines . The modern extended sense is mostly restricted to North American English, which uses "grapevine" to refer to the grape-bearing Vitis species...
s and stemStem may refer to:* Plant stem, the above ground structures that have vascular tissue and that support leaves and flowers* Word stem, the base part of a word not including inflectional morphemes...
s.
- Lamp black was traditionally produced by collecting soot, also known as lampblack, from oil lamp
An oil lamp is a simple vessel used to produce light continuously for a period of time from an oil-based fuel source. The use of oil lamps commences from prehistory and extends to the present day....
s.
Newer methods of producing carbon black have superseded these traditional sources, although some materials are still produced using traditional methods. For
artisanAn artisan is a skilled manual worker who crafts items that may be functional or strictly decorative, including furniture, clothing, jewelry, household items, and tools...
al purposes, it is very useful.
Surface chemistry
All carbon blacks have
chemisorbedChemisorption is a classification of adsorption characterized by a strong interaction between an adsorbate and a substrate surface, as opposed to physisorption which is characterized by a weak Van der Waals force. A distinction between the two can be difficult and it is conventionally accepted...
oxygenOxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...
complexesIn chemistry, a coordination complex or metal complex, is a structure consisting of a central atom or ion , bonded to a surrounding array of molecules or anions ....
(i.e.,
carboxylicA carboxyl group is a set of four atoms bonded together and present in carboxylic acids, including amino acids. Usually abbreviated as either CO2H or COOH, this set of atoms constitutes a functional group. In every carboxyl group the carbon atom is attached to an oxygen atom by a...
, quinonic, lactonic,
phenolicIn organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group bonded directly to an aromatic hydrocarbon group...
groups and others) on their surfaces to varying degrees depending on the conditions of manufacture. These surface oxygen groups are collectively referred to as volatile content. It is also known to be a non-conductive material due to its volatile content.
The coatings and inks industries prefer grades of carbon black that are
acidAn acid is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity greater than in pure water, i.e. a pH less than 7.0...
oxidized. Acid is sprayed in high
temperatureIn physics, temperature is a physical property of a system that underlies the common notions of hot and cold; something that feels hotter generally has the higher temperature. Temperature is one of the principal parameters of thermodynamics...
dryer- Drying :Drying of Bioproducts is a mass transfer process resulting in the removal of water moisture or moisture from another solvent, by evaporation from a solid, semi-solid or liquid to end in a solid state. To achieve this, there must be a source of heat, and a sink of the vapor thus produced...
s during the
manufacturingManufacturing is the use of machines, tools and labor to make things for use or sale. The term may refer to a range of human activity, from handicraft to high tech, but is most commonly applied to industrial production, in which raw materials are transformed into finished goods on a large scale...
process to change the inherent surface chemistry of the black. The amount of chemically-bonded oxygen on the
surface areaSurface area is the measure of how much exposed area a solid object has, expressed in square units. Mathematical description of the surface area is considerably more involved then the definition of arc length of a curve. For polyhedra the surface area is the sum of the areas of its faces...
of the black is increased to enhance performance characteristics.
External links
- Carbon black - NIOSH Pocket Guide to Chemical Hazards, CDC
The Centers for Disease Control and Prevention is a United States federal agency under the Department of Health and Human Services based in Atlanta, Georgia. It works to protect public health and safety by providing information to enhance health decisions, and it promotes health through...
Website Entry
- Carbon Black Industry from the Handbook of Texas
The Handbook of Texas is a comprehensive encyclopedia of Texas geography, history, and historical persons published by the Texas State Historical Association . The original Handbook was the brainchild of TSHA President Walter Prescott Webb of The University of Texas history department...
Online
- carbon-black.org-International Carbon Black Association