Aerosol spray is a type of dispensing system which creates an aerosol mist of liquid particles. Particulates, alternatively referred to as particulate matter (PM or fine particles, are tiny particles of solid or liquid suspended in a gas This is used with a can or bottle that contains a liquid under pressure. Aerosol spray is a type of dispensing system which creates an aerosol mist of liquid particles A bottle is a container with a neck that is narrower than the body and a "mouth When the container's valve is opened, the liquid is forced out of a small hole and emerges as an aerosol or mist. Particulates, alternatively referred to as particulate matter (PM or fine particles, are tiny particles of solid or liquid suspended in a gas Mist is a phenomenon of small droplets suspended in Air. It can occur as part of natural Weather or Volcanic activity and is common in cold air above As gas expands to drive out the payload, some propellant evaporates inside the can to maintain an even pressure. Outside the can, the droplets of propellant evaporate rapidly, leaving the payload suspended as very fine particles or droplets. Typical liquids dispensed in this way are insecticides, deodorants and paints. An insecticide is a Pesticide used against Insects in all developmental forms Deodorants are substances applied to the body particularly the Armpits mainly to reduce Body odor caused by the bacterial breakdown of Perspiration. Aerosol paint (spray paint – Paint in a sealed pressurized container that is released in a fine spray mist when depressing a Valve button located on the top of An atomiser is a similar device that is pressurised by a hand-operated pump rather than by stored gas. In Atomic spectroscopy, atomization stands for the conversion of a vaporized sample into atomic components
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History
The concepts of aerosol probably dates back to 1790. [1] The first aerosol spray can was invented in Oslo in 1926 by Erik Rotheim, a Norwegian chemical engineer. (called Christiania from 1624 to 1878 and Kristiania from 1878 to 1924 is the Capital and largest city of Norway. Norway ( Norwegian: Norge ( Bokmål) or Noreg ( Nynorsk) officially the Kingdom of Norway, is a Constitutional [1] The patent was sold to a US company for 100,000 Norwegian kroners. The krone ( sign: kr; code: NOK) is the Currency of Norway. The plural form is kroner. The Norwegian Post Office celebrated the invention by issuing a stamp in 1998. [2]
In 1941 the aerosol spray can was first put to good use by Americans Lyle Goodloe and William Sullivan, who are credited as the inventors of the modern spray can. The United States of America —commonly referred to as the [3] Their design of a refillable spray can (dubbed the “bug bomb”) patented in 1943 is the ancestor of many spray products. Pressurized by liquefied gas, the small portable can enabled soldiers to defend against malaria-carrying bugs by spraying inside tents in the Pacific during World War II. Malaria is a vector -borne Infectious disease caused by Protozoan Parasites It is widespread in tropical and subtropical regions including A tent is a shelter consisting of sheets of fabric or other material draped over or attached to a frame of poles or attached to a supporting rope The Pacific Ocean is the largest of the Earth 's Oceanic divisions World War II, or the Second World War, (often abbreviated WWII) was a global military conflict which involved a majority of the world's nations, including [4] In 1948, three companies were granted licenses by the United States government to manufacture aerosols. Two of the three companies still manufacture aerosols to this day, Chase Products Company and Claire Manufacturing. The "crimp-on valve", used to control the spray was developed in 1949 by Bronx machine shop proprietor Robert H. Abplanalp. Robert Henry (Bob Abplanalp ( April 4, 1922, New York City - August 30, 2003, Bronxville New York) was a Swiss-American [3]
Technology (aerosol propellants)
If the can was simply filled with compressed gas, either it would need to be at a dangerously high pressure, or the amount of gas in the can would be small, and would rapidly deplete. Usually the gas is the vapour of a liquid with boiling point slightly lower than room temperature. A vapor or vapour (see Spelling differences) is a substance in the Gas phase at a Temperature lower than its Critical temperature The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid Room temperature (also referred to as ambient temperature) is a common term to denote a certain Temperature within enclosed space at which humans are accustomed This means that inside the pressurised can, the vapour can exist in equilibrium with its bulk liquid at a pressure that is higher than atmospheric pressure (and able to expel the payload), but not dangerously high. In Thermodynamics, a thermodynamic system is said to be in thermodynamic equilibrium when it is in thermal equilibrium Mechanical equilibrium, and As gas escapes, it is immediately replaced by evaporating liquid. Since the propellant exists in liquid form in the can, it should be miscible with the payload or dissolved in the payload.
Chlorofluorocarbons (CFCs) were once often used, but since the Montreal Protocol came into force in 1989, they have been replaced in nearly every country due to the negative effects CFCs have on Earth's ozone layer. The haloalkanes (also known as halogenoalkanes or alkyl halides) are a group of Chemical compounds consisting of Alkanes such as Methane For other similarly-named agreements see Montreal Convention (disambiguation. The photochemical mechanisms that give rise to the ozone layer were worked out by the British physicist Sidney Chapman in 1930 The most common replacements are mixtures of volatile hydrocarbons, typically propane, n-butane and isobutane. In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. Propane is a three- Carbon Alkane, normally a gas but compressible to a liquid that is transportable Butane, also called n -butane, is the unbranched Alkane with four Carbon Atoms CH3CH2CH2CH3 Isobutane, also known as methylpropane or 2-methylpropane, is an Alkane, Isomeric with Butane. Dimethyl ether (DME) and methyl ethyl ether are also used. Dimethyl ether is the organic compound with the formula CH3OCH3 Methoxyethane, also known as methyl ethyl ether, is a colorless gaseous Ether with a medicine-like odor All these have the disadvantage of being flammable. Nitrous oxide and carbon dioxide are also used as propellants to deliver foodstuffs (for example, whipped cream and cooking spray). Nitrous oxide, commonly known as " laughing gas," is a Chemical compound with the Chemical formula N 2 O. Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single For the 1993 hip-hop single by the Wu-Tang Clan see CREAM CREAM is an acronym for Cognitive Reliability Error Analysis Method a Cooking spray is a spray form of various types of oils combined with Lecithin, an emulsifier and a propellent such as food-grade alcohol Nitrous oxide, Carbon Medicinal aerosols such as asthma inhalers use hydrofluoroalkanes (HFA): either HFA 134a (1,1,1,2,-tetrafluoroethane) or HFA 227 (1,1,1,2,3,3,3-heptafluoropropane) or combinations of the two. metered-dose inhaler (MDI is a device that helps deliver a specific amount of medication to the Lungs usually by supplying a short burst of aerosolized medicine that is inhaled
Packaging
Modern aerosol spray products have three major parts; the can, the valve and the actuator or button. The can is most commonly lacquered tinplate (steel with a layer of tin) and may be made of 2 or 3 pieces of metal crimped together. Tinplate is sheet steel covered with a thin layer of Tin. Before the advent of cheap mild steel the backing metal was iron. Aluminium cans are also common and are generally used for more expensive products. WikipediaNaming The valve is crimped to the rig of the can, the design of this component is important in determining the spray rate. The actuator is depressed by the user to open the valve; the shape and size of the nozzle in the actuator controls the spread of the aerosol spray.
Packaging that uses a piston barrier system is often used for highly viscous products such as post-foaming hair gels, thick creams and lotions, food spreads and industrial products and sealants. The main benefit of the piston barrier system is that is assures separation of the product from the propellant, maintaining the purity and integrity of the formulation throughout its consumer lifespan. The piston barrier system also provides a controlled and uniform product discharge rate with minimal product retention and is economical. CCL Container, North America’s leading producer of impact-extruded aluminum packaging, has successfully launched a number of niche food brands such as cheese spreads, cake icing, pan and cooking sprays and food preservative sprays using the piston barrier system in a side range of shapes, styles and sizes. The piston barrier system from CCL Container conforms to FD requirements for most food products.
Another type of dispensing system is the bag-in-can system (or BOV “bag on valve”). This system separates the product from the pressurizing agent with a hermetically-sealed, multi-layered laminated pouch, which maintains complete formulation integrity so only pure product is dispensed. Among its many benefits, the bag-in-can system extends a product’s shelf life. The bag-on-valve, or ABS, is widely used by sun care marketers for its benefits: all-attitude (360-degree) dispensing, quiet and non-chilling discharge. This bag-in-can system is also used in the packaging of pharmaceutical, industrial, household, pet care and other products that require complete separation between the product and the propellant.
Health concerns
There are two main areas of health concern linked to aerosol cans:
- Deliberate inhalation of the contents to gain a high from the propellant
- The piggy-backing of more dangerous particles into the respiratory tracts
See also
References
- ^ a b Bellis, Mary The History of Aerosol Spray Cans
- ^ Image of the Norway Postage stamp
- ^ a b Kimberley A. Aerosol paint (spray paint – Paint in a sealed pressurized container that is released in a fine spray mist when depressing a Valve button located on the top of Air pollution is the human introduction into the atmosphere of Chemicals Particulate matter, or Biological materials that cause harm or discomfort The haloalkanes (also known as halogenoalkanes or alkyl halides) are a group of Chemical compounds consisting of Alkanes such as Methane Ozone depletion describes two distinct but related observations a slow steady decline of about 4 percent per decade in the total amount of Ozone in Earth's Nitrous oxide, commonly known as " laughing gas," is a Chemical compound with the Chemical formula N 2 O. Packaging is the science art and technology of enclosing or protecting products for distribution storage sale and use McGrath (Editor), Bridget E. Travers (Editor). World of Invention "Summary". Detroit: Thomson Gale. ISBN 0-7876-2759-3.
- ^ Core, Jim, Rosalie Marion Bliss, and Alfredo Flores. (September 2005) "ARS Partners With Defense Department To Protect Troops From Insect Vectors". Agricultural Research MagazineVol. 53, No. 9 .
Further reading
- Brody, A. L. , and Marsh, K, S. , "Encyclopedia of Packaging Technology", John Wiley & Sons, 1997, ISBN 0-471-06397-5
- ASTM D3069 Delivery Rate of Aerosol Products
- ASTM D3065 Flammability of Aerosol Products
- ASTM D3094 Seepage Rate of Aerosol Products
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