Comprehensive Facts & Figures on VAE - Wacker Chemie AG

Comprehensive Facts & Figures on VAE

Vinyl acetate-ethylene (VAE) dispersions and dispersible powders are made by the emulsion copolymerization of vinyl acetate and ethylene. Vinyl acetate homopolymers are hard and polar, while ethylene forms polymers that are soft and hydrophobic. Consequently, the ethylene acts as an internal flexibilizer for the hard vinyl acetate component of the copolymer. VAEs therefore do not require an external plasticizer.

Ethylene Properties:

  • Tg ~ -125 °C (soft)
  • Non-polar, hydrophobic
  • Permanent flexibility
  • High saponification resistance
  • Forms ideal copolymers with vinyl acetate
  • Flammable gas

Vinyl Acetate Properties:

  • Tg ~ 32 °C (hard)
  • Polar, hydrophobic
  • Tough
  • Basic raw material

VAE Copolymer Dispersion Properties:

  • Tg varies from +25 to -25 °C in accordance with the ethylene content
  • Excellent film-forming properties – no solvents needed (enables formulators to design waterborne products with the lowest possible VOC content)
  • Permanently flexible polymer films – no migration of plasticizers
  • Good adhesion to non-polar substrates
  • Better water and saponification resistance

Vinyl acetate-ethylene (VAE) is a combination of ethylene and vinyl acetate - two monomers possessing special properties. Polymerization leads to VAE copolymers. VAE copolymers form the basis for engineering different properties in the individual end application.

Many polymeric dispersions supplied by the chemical industry are produced at atmospheric pressure. This is not the case for VAE dispersions since ethylene is a gas and high pressure is required to incorporate it into the polymer chain. In the emulsion polymerization process, vinyl acetate and ethylene are polymerized in water with colloidal stabilization.

VAE dispersible powders are made by spray-drying the dispersion after the polymerization process.

Dispersions with ethylene – high demands on equipment

In past decades, the petrochemical industry was based on crude oil. However, the various petrochemical value chains have been radically reshaped by persistently high oil prices and the advent of fresh petrochemical feedstocks from carbon sources such as shale gas and biomass.

Petrochemicals are increasingly being produced from multiple sources and feedstock diversification has become a strategic focus in the various geopolitical regions. For example, the abundance of shale gas in the United States has started to impact the market for ethylene and its derivatives. Other feedstocks that may impact markets in the future are coal and biomass. Feedstock diversification will increasingly influence how refineries and the adjacent olefin crackers are operated. Output from the petrochemical building blocks can be expected to change accordingly.

In addition, environmental and market conditions are becoming increasingly pressing issues for the petrochemical industry. Hence, judicious choice of feedstock and strategic orientation of the petrochemical value chain will be key issues in the years to come.

Given these ongoing changes and uncertainties, it is therefore wise to pursue a strategy of stability. In this regard, vinyl acetate-ethylene copolymers (VAE) derived from sustainable C1 and C2 value chains offer reliabiity and desirable long-term advantages. The feedstock versatility of C1 chemistry reduces price volatility, leading to a reliable value chain marked by high carbon efficiency.