What kind of material is foam

What is EVA foam / EVA material & what is it made of?

What is EVA foam

The abbreviation EVA is the abbreviation for ethylene-vinyl acetate copolymer. Another abbreviation for the term is EVAC. It is a specific copolymer made from the raw materials ethylene and vinyl acetate. EVA is very light and colorless. The ethylene and the vinyl acetate can be used in any mixing ratio. EVA is also a non-toxic material. It does not contain any plasticizers or other additives.

properties

EVA can appear in different consistencies and forms. It is available both as granules and as a dispersion, as a powder or in solid form as a film and plastic. One of the special properties of EVA is that it is particularly heat-resistant and has a very high durability. Depending on the proportions of ethylene and vinyl acetate, both the properties and the possible uses vary. In principle, EVA is very resistant to acids such as hydrochloric acid, nitric acid or sulfuric acid. The substance does not accept any damage from alcohol, hydrogen peroxide or hydrocarbons. The same applies to UV radiation. This allows the material to be sterilized.

The production

EVA is produced in a similar way to PE-LD. It can be made in either a high pressure or a low pressure process. In the high-pressure process, polymerization takes place, which is caused by a large pressure development. A high level of heating then takes place, as a result of which granules are formed. Catalysts are used in the low-pressure process. The process is supported by solution polymerisation, suspension polymerisation or gas phase polymerisation. In the first case, a distillation then takes place, which separates the product from the solution. Hydrocarbons or gasoline are used in suspension polymerization. - The fabric is polymerized by heat and pressure. The separation then takes place. The last method uses a catalyst. High temperatures and pressure also come into play. Ethene creates a state of suspension, after which the finished polymer falls off in powder form.

The usage

EVA improves the properties of products - especially foils. The so-called elongation at break is increased. If you add other mineral or oxidic substances to the material, a plastic can acquire completely new properties. It can suddenly be magnetizable or absorb radiation, which makes it suitable for use in the medical field of X-rays.

There are also special areas of application. These include films from agriculture, shrink-wrapping films or floor coverings, shower curtains or cables. With a higher proportion of vinyl acetate, EVA can also be used as a hot melt adhesive. This can bind fibers. This is required, for example, in the manufacture of tufted carpets or needle punched nonwovens. In addition, the book cover and the side connection can be made with EVA. The heat-sealing property can also ensure a water-repellent impregnation. The material is also used in boat building.

If the vinyl acetate content is between 30 and 90%, a rubber-like elastomer is obtained. This can then be found in shoe soles, for example. These have the property of being particularly abrasion-resistant.
Another area of ‚Äč‚Äčapplication is photovoltaics. Here you can encase the solar cells with EVA. It does this through amalgamation. The network then remains in place.

EVA foam can also be found in cosmetics. Here it is often used in peelings.

In the field of chemistry, EVA is also used as a base material for particularly elastic hoses, which can provide high performance. The hoses do not have any pores and are particularly abrasion-resistant. Gas can only penetrate to a very limited extent, as can carbon dioxide. The hoses are also ideal for use in dispensing systems. Seals are also often made from EVA.