Aerosol propellant

An aerosol propellant is a compressed or liquefied gas that supplies pressure to expel a product from an aerosol container. It may also help disperse the product into droplets or particles.

Aerosol: A suspension of liquid droplets or solid particles in a gas. A propellant creates the dispersed droplets or particles that make a product an aerosol.
Chlorofluorocarbon: A compound containing carbon, chlorine, and fluorine, formerly used widely as an aerosol propellant. CFC propellants served many aerosol products before ozone-depletion concerns drove restrictions.
Liquefied gas: A substance stored as a liquid under pressure that becomes gas when pressure is reduced. Many aerosol propellants are liquefied gases that provide sustained pressure as they vaporize.
Montreal Protocol: An international treaty adopted in 1987 to phase out ozone-depleting substances. Its controls on CFCs prompted the replacement of many aerosol propellants.
Aerosol valve: A valve that controls the release of product and propellant from an aerosol container. Opening the valve lets internal pressure drive the formulation through the actuator.
Hydrocarbon propellant: A flammable propellant, commonly propane, n-butane, or isobutane, used in aerosol products. Hydrocarbons are common alternatives where their flammability can be managed.
Compressed gas: A gas stored under pressure in a container. Compressed-gas propellants generally lose pressure as gas is dispensed, unlike liquefied propellants.
Ozone layer: The region of the stratosphere with elevated concentrations of ozone that absorbs much of the Sun's ultraviolet radiation. Propellant-related ozone depletion threatened this protective atmospheric region.
Vapor pressure: The pressure exerted by a vapor in equilibrium with its condensed phase at a given temperature. Liquefied propellants replenish vapor as gas leaves, helping maintain container pressure.
Dimethyl ether: A flammable liquefied gas used as an aerosol propellant and solvent. It can propel products while also dissolving some formulation ingredients.

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