Moisture issue in EVA process 1

[efoster1973]

Hi All,

during manufacture of an EVA based masterbatch, a smell of acetic acid is noticable ( I assume this is a result of hydrolysis?) Are there any additives available to mop up excess moisture from the raw materials that we can use during the process? Or any other way to reduce the production of acetic acid during the process?

Thanks in advance

 

[Demon3]

Can you add a little calcium carbonate? The EVA will no longer be transparent but CaCO3 is great for adsorbing acids like acetic acid. Try 1 weight % for a starting point. A standard grade would have a mean particle size around 2 microns, largest particles below 10 microns. Large companies you could contact include Omya and Imerys. Explain to them what you want it for and make sure you don't buy a grade that's precoated with stearic acid / stearate because that type won't be able to adsorb your acetic acid. The CaCO3 should be 100-150 Euro per ton delivered as a guess.

 

[Demon3]

Grades you might try include Omyacarb 2AV from Omya or Carbital 110 from Imerys.

 

[efoster1973]

Thanks Demon3, am looking into that. Also looking at Calcium oxide as a desiccant, do you have any experience of this? I'm not a polymer chemist and wonder if there would be any significant effects to the physical properties of the final products should either of these additives be included in the formulation?

 

[Demon3]

Luckily I have lots of experience on adding particulates to polymers and effects on properties. I don't think 1-2 % of fine particles won't have any effect on EVA, just don't add anything with big particles as that's more likely to reduce elongation to break and impact resistance.