EVOH
Encyclopedia
Ethylene Vinyl Alcohol, commonly abbreviated EVOH, is a formal copolymer of ethylene
and vinyl alcohol. Because the latter monomer
mainly exists as its tautomer
acetaldehyde
, the copolymer is prepared by polymerization of ethylene and vinyl acetate
to give the ethylene vinyl acetate (EVA) copolymer followed by hydrolysis. The plastic
resin is commonly used in food applications, and it has lately found application in plastic gasoline tanks for automobiles. Its primary purpose is to provide barrier properties, primarily as an oxygen barrier for improved food packaging shelf life and as a hydrocarbon barrier for fuel tanks. EVOH is typically coextruded or laminated as a thin layer between cardboard, foil, or other plastics. EVOH copolymer is defined by the mole % ethylene content: lower ethylene content grades have higher barrier properties; higher ethylene content grades have lower temperatures for extrusion
.
(Belgium) the biggest production facility of the world with a capacity of 24.000 ton/a.
Nippon Gohsei has three (3) production sites in Japan, US and Europe.
In 2004, Nippon Gohsei started production at its Hull, UK, site having the world's largest single line capacity.
It is sold under the trade name SoarnoL.
. Dissolved in dimethyl-sulfoxide
(DMSO) and mixed with a radiopaque substance Ethylene Vinyl Alcohol Copolymer is used to embolise
blood vessel
s.
Ethylene
Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...
and vinyl alcohol. Because the latter monomer
Monomer
A monomer is an atom or a small molecule that may bind chemically to other monomers to form a polymer; the term "monomeric protein" may also be used to describe one of the proteins making up a multiprotein complex...
mainly exists as its tautomer
Tautomer
Tautomers are isomers of organic compounds that readily interconvert by a chemical reaction called tautomerization. This reaction commonly results in the formal migration of a hydrogen atom or proton, accompanied by a switch of a single bond and adjacent double bond...
acetaldehyde
Acetaldehyde
Acetaldehyde is an organic chemical compound with the formula CH3CHO or MeCHO. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale industrially. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants as part...
, the copolymer is prepared by polymerization of ethylene and vinyl acetate
Vinyl acetate
Vinyl acetate is an organic compound with the formula CH3COOCH=CH2. A colorless liquid with a pungent odor, it is the precursor to polyvinyl acetate, an important polymer in industry.-Production:...
to give the ethylene vinyl acetate (EVA) copolymer followed by hydrolysis. The plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
resin is commonly used in food applications, and it has lately found application in plastic gasoline tanks for automobiles. Its primary purpose is to provide barrier properties, primarily as an oxygen barrier for improved food packaging shelf life and as a hydrocarbon barrier for fuel tanks. EVOH is typically coextruded or laminated as a thin layer between cardboard, foil, or other plastics. EVOH copolymer is defined by the mole % ethylene content: lower ethylene content grades have higher barrier properties; higher ethylene content grades have lower temperatures for extrusion
Extrusion
Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section...
.
Industrial Production
The company EVAL Europe started up in 2004 in ZwijndrechtZwijndrecht, Belgium
Zwijndrecht is both a village and a municipality located in the Flemish province of Antwerp, in Belgium. As well as Zwijndrecht proper, the municipality includes the villages of Burcht. As of January 1, 2006, Zwijndrecht had a total population of 18,231....
(Belgium) the biggest production facility of the world with a capacity of 24.000 ton/a.
Nippon Gohsei has three (3) production sites in Japan, US and Europe.
In 2004, Nippon Gohsei started production at its Hull, UK, site having the world's largest single line capacity.
It is sold under the trade name SoarnoL.
Use in medical applications
EVOH is used in liquid embolic system in inverventional radiology, e.g. in OnyxOnyx (Interventional radiology)
In interventional radiology Onyx is a trade name for a copolymer uesd for embolisation therapy, which involves the occlusion of blood vessels. It is a liquid embolic agent. Onyx is produced and sold by ev3 Inc. - Components :...
. Dissolved in dimethyl-sulfoxide
Dimethyl sulfoxide
Dimethyl sulfoxide is an organosulfur compound with the formula 2SO. This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water...
(DMSO) and mixed with a radiopaque substance Ethylene Vinyl Alcohol Copolymer is used to embolise
Embolization
Embolization is a non-surgical, minimally-invasive procedure performed by an interventional radiologist and interventional neuroradiologists. It involves the selective occlusion of blood vessels by purposely introducing emboli.-Therapeutic applications:...
blood vessel
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
s.