Dispersions

At a Glance

WACKER has manufactured dispersions based on poly(vinyl acetate) (PVAc) on an industrial scale since 1938. The ongoing development and enhancement of the technology continually opens up new innovative technologies: the first copolymer dispersion without the addition of plasticizers, the development from a dispersion into a patented dispersible polymer powder, and the discovery of VAE (vinyl acetate-ethylene) technology for sustainable VAE copolymer dispersions, with applications such as water-based adhesives. The dispersions are marketed under the trade name VINNAPAS® and VINNOL® Vinnacoat, and are suitable for use as high-quality environmentally friendly polymer binders for various applications, where they optimize products and processes in a number of ways.

Thanks to VINNAPAS® dispersions based on to vinyl acetate-ethylene (VAE) or vinyl chloride-ethylene (VC-E), paints and coatings can be formulated as low-VOC products, offering outstanding wet-scrub resistance, good color fastness, high abrasion and water resistance, and reduced dirt pick-up.

In construction applications such as plasters and renders, EIFS/ETICS systems, waterproofing membranes and paste tile adhesives, as well as very generally in cement mixes, VAE copolymer dispersions reinforce the properties of the end product, such as adhesion and cohesion (bonding), flexibility and processability.

Waterborne adhesives modified with VINNAPAS® copolymer dispersion or VINNAPAS® (poly(vinyl acetate)) homopolymer dispersions for paper and packaging, wood and furniture lamination and for floor coverings, provide excellent adhesion, high heat resistance, good water resistance, high processing speeds and a wide range of formulations.

Dispersions based on VAE and VC-E copolymers are used in nonwovens and textiles, such as serviettes, moist wipes and air filters to provide the end product with superb wet and dry tear strength, a pleasant feel, absorption, flame retardance and abrasion resistance, as well as dimensional stability. In carpet backings for tufted carpets, needlefelt, woven or flock carpets, and tapestries, VAE or VC‑E-based dispersions ensure the required resistance, flexibility and compliance with emission limits.

Paper coatings can be modified with VINNAPAS® VAE copolymer dispersions that meet the high requirements made for competitive products in the paper and board coating industries.

Dispersion is defined by the following criteria:

Macroscopic appearance

  • White / transparent liquid
  • Water as a liquid medium

Microscopic appearance

  • Solid, spherical polymer particles in water
  • Particle diameter: 50 – 5,000 nm
  • Solids content up to 74% (normally 50%)
  • Over 104 – 109 particles per liter of dispersion
  • Stabillization system (anionic, cationic or steric)

Dispersions can be produced at atmospheric pressure or under pressure. Atmospheric pressure polymerization takes place under normal conditions. A typical example is the production of styrene-acrylate and VAC-VeoVa dispersions. Pressurized polymerization is much more complicated and costly. Not every manufacturer of dispersions and dispersible polymer powders in the world has such facilities and is therefore capable of producing ethylene-based polymer dispersions.

Production of VAE Dispersions