EVOH (Ethylene-Vinyl Alcohol Copolymer) Storage & Tank Compatibility

Storing EVOH (Ethylene-Vinyl Alcohol Copolymer)? Start Here

EVOH, or ethylene-vinyl alcohol copolymer (_C4H8O repeat unit, CAS 103812-69-7), is a high-performance thermoplastic barrier resin produced by hydrolyzing an ethylene-vinyl acetate copolymer to convert the acetate groups into hydroxyl groups. The result is a crystalline, food-contact-grade polymer prized for its exceptional resistance to oxygen, carbon dioxide, and hydrocarbon permeation - properties that make it the central barrier layer in multilayer packaging, fuel tanks, and flexible films. It is supplied as pellets, powder, finished film, and as water-borne or alcohol-water dispersions for coating applications. As a high-molecular-weight solid copolymer, EVOH itself carries no harmonized GHS hazard classification and is chemically inert under normal handling. Storage questions therefore center on the physical form being held - dry resin versus a liquid dispersion - rather than on aggressive chemical attack.

Storing EVOH in Polyethylene (HDPE / XLPE) Tanks and Vessels

For the forms a tank actually holds - dry pellets, powder, and water-borne or alcohol-water EVOH dispersions - polyethylene is an excellent and fully compatible material of construction. HDPE and crosslinked polyethylene (XLPE) are themselves inert barrier resins; EVOH and its typical aqueous or short-chain-alcohol carriers do not chemically attack, swell, or degrade the tank wall at ambient temperature. This places EVOH solidly in the compatible (S) category for normal storage and dispersion handling.

The one honest limitation is heat, not chemistry. EVOH melts in the range of roughly 160 to 190 C, far above the service temperature of any polyethylene vessel, which begins to soften well below 100 C. Molten EVOH at extrusion temperature must be handled exclusively in stainless steel melt and process equipment - never in a plastic tank. If a dispersion grade uses an alcohol cosolvent such as n-propanol, confirm the carrier flash point and treat the vessel as you would for that flammable carrier, including bonding, grounding, and vapor control. Keep dry pellets and powder dry and away from ignition sources, since finely divided organic powder can present a dust hazard.

Material compatibility at a glance

For dry EVOH pellets or powder and for water-borne or alcohol-water EVOH dispersions, HDPE and XLPE polyethylene tanks are an excellent, fully compatible choice - polyethylene is itself an inert barrier resin and is not attacked by the copolymer or its typical carriers. Use PE only for ambient-temperature solids storage and dispersion handling; never for molten resin, which must be processed in stainless steel extrusion and melt equipment.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• EVOH copolymer carries no GHS hazard classification, but always read the supplier Safety Data Sheet for the specific grade or dispersion, since carrier solvents can add flammability and exposure hazards.
• Store dry pellets and powder in a cool, dry, well-ventilated area away from heat and ignition sources; control airborne dust to avoid a combustible-dust atmosphere.
• Handle alcohol-water dispersions as flammable liquids when an alcohol cosolvent is present - bond and ground transfer equipment and limit vapor accumulation.
• Never store or convey molten EVOH in polyethylene equipment; melt processing belongs in stainless steel extruders and hoppers rated for 160 to 190 C and above.
• Use general ventilation during melt processing; thermal decomposition can release acetic acid and other vapors at elevated temperatures.
• Protect EVOH and its dispersions from prolonged moisture pickup where it would harm downstream barrier performance, and follow food-contact handling controls for packaging-grade material.

Common questions

Can I store EVOH in an HDPE or XLPE polyethylene tank?

Yes. For dry pellets, powder, and water-borne or alcohol-water dispersions, HDPE and XLPE are fully compatible. Polyethylene is itself an inert barrier resin and is not attacked by EVOH or its typical carriers at ambient temperature. The only restriction is that the tank must not be used for molten resin.

Is EVOH a hazardous chemical?

The solid copolymer is not classified as hazardous under GHS and carries no signal word or hazard codes in PubChem. Any hazard you encounter comes from a dispersion carrier solvent rather than the polymer itself, so always check the specific grade's Safety Data Sheet.

Why can't a plastic tank hold molten EVOH?

EVOH melts at roughly 160 to 190 C, while polyethylene vessels soften well below 100 C. Molten resin must be handled in stainless steel extrusion and melt equipment; only ambient-temperature solids and dispersions belong in a PE tank.

What is EVOH made from?

EVOH is produced by hydrolyzing an ethylene-vinyl acetate copolymer, converting the acetate groups to hydroxyl groups. This is why vinyl acetate monomer and polyvinyl alcohol are chemically related materials in its family.