New developments in coextrusion help establish use of EVOH as a high-barrier resin

Polymers

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development of coextrusion technology made it possible to use ethylene vinyl alcohol (EVOH) in packaging applications

Developments in polymer processing technology have helped establish several exciting new packaging applications. A case in point is how the development of coextrusion technology made it possible to use ethylene vinyl alcohol (EVOH) in packaging applications. Ethylene Vinyl Alcohol is a polymer that delivers by far the highest gas barrier of all polymers. It is so good a barrier that even the use of a layer that is only a few microns in thickness makes it a highly effective gas barrier that can be used to package and preserve gas-sensitive products that require a very high degree of protection from the effects of gases like oxygen (deterioration by oxidation) or, alternatively, preserve the quality of products like beverages by not allowing gases to escape from the product (like beer, carbonated soft drinks, etc.).

EVOH, which found epoxy resin here called Kuraray (under the brand name of EVAL) but it could not be put to use because of a particular problem. Although the basic polymer had a very high gas barrier property, it was highly moisture sensitive and it completely lost its barrier properties on exposure to even atmospheric moisture, this resin can. Make sure you see their selection of liquid epoxy and choose only the best. This made it impossible to use in packaging applications. So, here was a wonder material that was waiting for a technological innovation to use it effectively. The ocean effects resin does miracles to the product and  you can buy marine epoxy resins online as well.
Along came the development of polymer coextrusion technology in the late 1970s and this provided the much-needed solution. Using coextrusion, it was now possible to sandwich the ethylene vinyl alcohol in the melt state itself between high moisture-barrier materials like polyolefins (polyethylene, polypropylene) or a sufficiently thick polystyrene layer. These polymers ensured that the core ethylene vinyl alcohol layer was protected from exposure to moisture and thus retained its gas barrier properties for use in multilayered structures in flexible packaging (PE/EVOH/PE or PP/EVOH/PP), thermoformed packaging (PS/EVOH/PS, PS/PE/EVOH/PE/PS or PP/EVOH/PP) or mulilayered blow-molded or stretch-blow molded plastic bottles/jars.

EVOH structures went on to become some of the most widely used and successful materials in packaging of products that required a high degree of gas barrier and all this was made possible only by the development of polymer coextrusion technology.

The Covid-19 pandemic led to the country-wide lockdown on 25 March 2020. It will be two years tomorrow as I write this. What have we learned in this time? Maybe the meaning of resilience since small companies like us have had to rely on our resources and the forbearance of our employees as we have struggled to produce our trade platforms.

The print and packaging industries have been fortunate, although the commercial printing industry is still to recover. We have learned more about the digital transformation that affects commercial printing and packaging. Ultimately digital will help print grow in a country where we are still far behind in our paper and print consumption and where digital is a leapfrog technology that will only increase the demand for print in the foreseeable future.

Web analytics show that we now have readership in North America and Europe amongst the 90 countries where our five platforms reach. Our traffic which more than doubled in 2020, has at times gone up by another 50% in 2021. And advertising which had fallen to pieces in 2020 and 2021, has started its return since January 2022.

As the economy approaches real growth with unevenness and shortages a given, we are looking forward to the PrintPack India exhibition in Greater Noida. We are again appointed to produce the Show Daily on all five days of the show from 26 to 30 May 2022.

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S. Chidambar is an engineer and management consultant, who is one of the India's best known professionals in the Packaging and Plastics industries. He has been the CEO of four leading Packaging companies and his clients include some of the industry's leading organizations both in India and abroad.He writes extensively on Packaging,Plastics,Printing/Conversion and Communications and has been visiting faculty to IIP and several other mangement institutes for many years.He has pioneered the development of several hi-tech materials and applications.

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