EVOH (EVASIN)
| Click on MSDS or Technical Data Sheet under each grade to view the document EV-3201V MSDS Technical Data Sheet EV-3801V MSDS Technical Data Sheet EV-4405V MSDS Technical Data Sheet |
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| environmentally friendly compound - combines distinguished and very unique properties. It is extrudable and thermo-processable; foils show high transparency, weather resistant. No other polymer reaches its excellent properties concerning gas barrier, flavor barrier, aroma and spice preservation, oil and solvents resistance and hygroscopic behavior. EVASIN is transferred into foils, sheets or bottles for their excellent barrier effect against gases and organic liquids. The ethylene content of the polymer molecule influences this effect quite obviously, as seen from the figures in the table above. Ethylene contents more than 30 mol% are necessary to receive adequate water- resistance and insolubility on one side as well as sufficient thermo plasticity for the demanded thermoprocessability on the other side. Higher levels of ethylene – up to 38 mol% - facilitate workability and do not influence the desired barrier effect too much. 44 mol% show even easier processability, but there is already a slightly increased oxygen transmission in comparison to 32% or 38% EVOH. But even EVOH-types with ethylene contents of 40-50 mol % still have a remarkable higher barrier effect than any other organic foil. Also, the negative influence of residual acetyl-groups in EVOH can be estimated: They act as “spacers” leading to irregular zones along the polymer chain, this way reducing the necessary polar entanglement of EVOH molecules. The effect of this “molecular widening” is a tremendous loss of barrier effect. Because of the molecular design, EVASIN is insoluble in water, though hydrophilic. Therefore no surface electrostatic charge is noticed. That is an ideal property for wrapping electronic parts, being sensitive to electric sparks. Packaging and Wrapping of sensible Foodstuff Nitrogen Gas Barrier Sausage, already sliced in a central factory, cannot be sold in supermarkets except with a very special protection. Accordingly, the above mentioned trays and foils are used. But in addition, the space above the goods is flushed with nitrogen before sealing. In comparison to the anyway excellent barrier values against oxygen, EVASIN shows even much increased barrier effect – more than double - against nitrogen gas. Sealed EVOH packages keep ambient oxygen off and flushed nitrogen around the wrapped goods. This way a much longer storage lifetime (called: the “…Best-use-before-time…”) - can be announced for foodstuffs. Carbon dioxide Until recently, “bubbling” CO2 containing drinks were sold exclusively in glass bottles. The first attempts to use simple light weight PET bottles were only successful for water and soft drinks with no or low CO2 content and short shelf life. Reason is the relatively high CO2 gas transmission through all commonly known polymers. Obviously this gas dissolves much better in organics than oxygen or nitrogen. That is true also for EVOH, though here the transmission rates are much lower than in other organic foils: 4-times higher than the value for oxygen is still an exceptionally good barrier effect. Therefore, nowadays co-extruded PET/EVOH/PET bottles win more and more market share. They now guarantee a long storage time without loss of taste and sparkling/foaming effect, substituting even aluminium cans for beer. As those packaging can be recycled (the material sometimes being raw material for some other applications), they were looked upon as being environmentally friendly. And, by this way, the allover energy balance against glass or Aluminium is quite favourable. Water vapor The OH-groups in the polymer make EVOH a hydrophilic material: Remarkable sensitivity and transmission of water and humidity is given. If this should be avoided, again, appropriate coextruded foils and articles have to be used, with a “buried” interlayer of EVOH |