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| OtherNames = Ethenol, polymer with ethene
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| CASNo = 25067-34-9
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| Formula = (C<sub>2</sub>H<sub>4</sub>O-C<sub>2</sub>H<sub>4</sub>)<sub>x</sub>
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'''Ethylene vinyl alcohol''' ('''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. 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]].
'''Ethylene vinyl alcohol''' ('''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. 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]].


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It is also used as a hydrocarbon barrier in plastic fuel tanks and pipes.
It is also used as a hydrocarbon barrier in plastic fuel tanks and pipes.




== Industrial production ==
== Industrial production ==
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Because of the high capital cost to build an EVOH plant, and the complexity of making a food grade product, only a few companies produce EVOH:
Because of the high capital cost to build an EVOH plant, and the complexity of making a food grade product, only a few companies produce EVOH:


[[Kuraray]] produces EVOH resin under the name "EVAL," with 10,000 ton plant in Okayama, Japan; a 35,000 ton plant in the U.S. (near Houston, TX) under its subsidiary Kuraray America; and a 24,000 ton plant in Belgium under its subsidiary EVAL Europe.<ref>http://www.kuraray.co.jp/en/company/business/eval.html</ref>
[[Kuraray]] produces EVOH resin under the name "EVAL," with 10,000 ton plant in Okayama, Japan; a 35,000 ton plant in the U.S. (near Houston, TX) under its subsidiary Kuraray America; and a 24,000 ton plant in Belgium under its subsidiary EVAL Europe.<ref>[http://www.kuraray.co.jp/en/company/business/eval.html EVAL Division]</ref>


Nippon Gohsei produces EVOH under the trade name Soarnol. It has production sites in Misushima, Japan; La Porte, Texas in the USA; and Hull, England. <ref>[http://www.nippon-gohsei.com/ Nippon Gohsei – The right strategy to get the results] http://www.nippon-gohsei.com/</ref>
Nippon Gohsei produces EVOH under the trade name Soarnol. It has production sites in Misushima, Japan; La Porte, Texas in the USA; and Hull, England.<ref>[http://www.nippon-gohsei.com/ Nippon Gohsei – The right strategy to get the results]</ref>


Chang Chun Petrochemical produces EVOH under the trade name EVASIN. It has a single site in Taipei, Taiwan.
Chang Chun Petrochemical produces EVOH under the trade name EVASIN. It has a single site in Taipei, Taiwan.


== EVOH in Food Packaging ==
== Food packaging ==


Due to its strong barrier against oxygen and gas, food packaging manufacturers, including PremiumPack, use EVOH in their shrink vacuum bag structure to extend the shelf life of food products and protect their nutrients against bacteria. <ref>[http://premiumpack.at/technology/why-evoh PREMIUMPACK – Why EVOH?]</ref>
Due to its strong barrier against oxygen and gas, food packaging manufacturers, including PremiumPack, use EVOH in their shrink vacuum bag structure to extend the shelf life of food products and protect their nutrients against bacteria.<ref>[http://premiumpack.at/technology/why-evoh PremiumPack – Why EVOH?]</ref>


== Use in medical applications ==
== Medical applications ==


EVOH is used in a liquid embolic system in interventional radiology, e.g. in [[Onyx_(Interventional_radiology)|Onyx]].<ref>[http://www.ajnr.org/cgi/reprint/30/1/99 Embolization of Intracranial Arteriovenous Malformations with Ethylene-Vinyl Alcohol Copolymer (Onyx)]. American Journal of Neuroradiology 30:99-106, January 2009.</ref> Dissolved in [[dimethyl sulfoxide]] (DMSO) and mixed with a radiopaque substance, ethylene vinyl alcohol copolymer is used to [[Embolization|embolize]] [[blood vessel]]s.
EVOH is used in a liquid embolic system in interventional radiology, e.g. in [[Onyx_(Interventional_radiology)|Onyx]].<ref>{{Cite journal | url = http://www.ajnr.org/cgi/reprint/30/1/99 | title = Embolization of Intracranial Arteriovenous Malformations with Ethylene-Vinyl Alcohol Copolymer (Onyx) | journal = American Journal of Neuroradiology | volume = 30 | pages = 99-106 | date =2009}}</ref> Dissolved in [[dimethyl sulfoxide]] (DMSO) and mixed with a radiopaque substance, ethylene vinyl alcohol copolymer is used to [[Embolization|embolize]] [[blood vessel]]s.


== References ==
== References ==

Revision as of 13:47, 14 August 2015

Ethylene vinyl alcohol
Names
Other names
Ethenol, polymer with ethene
Identifiers
Properties
(C2H4O-C2H4)x
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Ethylene vinyl alcohol (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. 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.

The plastic resin is commonly used as an oxygen barrier in food packaging. It is better than other plastics at keeping air out and flavors in, is highly transparent, weather resistant, oil and solvent resistant, flexible, moldable, recyclable, and even printable. Its drawback is that it is difficult to make and therefore more expensive than other food packaging. Instead of making an entire package out of EVOH, manufacturers keep costs down by coextruding or laminating it as a thin layer between cardboard, foil, or other plastics.

It is also used as a hydrocarbon barrier in plastic fuel tanks and pipes.

Industrial production

Because of the high capital cost to build an EVOH plant, and the complexity of making a food grade product, only a few companies produce EVOH:

Kuraray produces EVOH resin under the name "EVAL," with 10,000 ton plant in Okayama, Japan; a 35,000 ton plant in the U.S. (near Houston, TX) under its subsidiary Kuraray America; and a 24,000 ton plant in Belgium under its subsidiary EVAL Europe.[1]

Nippon Gohsei produces EVOH under the trade name Soarnol. It has production sites in Misushima, Japan; La Porte, Texas in the USA; and Hull, England.[2]

Chang Chun Petrochemical produces EVOH under the trade name EVASIN. It has a single site in Taipei, Taiwan.

Food packaging

Due to its strong barrier against oxygen and gas, food packaging manufacturers, including PremiumPack, use EVOH in their shrink vacuum bag structure to extend the shelf life of food products and protect their nutrients against bacteria.[3]

Medical applications

EVOH is used in a liquid embolic system in interventional radiology, e.g. in Onyx.[4] Dissolved in dimethyl sulfoxide (DMSO) and mixed with a radiopaque substance, ethylene vinyl alcohol copolymer is used to embolize blood vessels.

References

  1. ^ EVAL Division
  2. ^ Nippon Gohsei – The right strategy to get the results
  3. ^ PremiumPack – Why EVOH?
  4. ^ "Embolization of Intracranial Arteriovenous Malformations with Ethylene-Vinyl Alcohol Copolymer (Onyx)". American Journal of Neuroradiology. 30: 99–106. 2009.