50 Years of VINNAPAS®

Usually invisible, but always indispensable: WACKER's dispersible polymer powders have been leaving their mark on the construction industry for more than 50 years now. Enabling high-quality mineral building materials with precisely defined technical properties, as well as opening up a great many novel applications and techniques, these powders help rationalize construction-site processing. In sum: VINNAPAS® polymer powders have revolutionized the construction sector.

Binders have been around for a very long time. For example, about 14,000 years ago, craftsmen in what is now eastern Turkey used quick lime to lay bricks. 3,000 years ago, the Phoenicians were the first to mix lime with volcanic rock, thereby producing a material that hardened even under water. In Roman times, the first impressive structures made with mortar were built, such as the Pont du Gard" in southern France.

Nowadays, the construction industry mainly hits the headlines when taller and taller buildings spring up. The Petronas Towers in Kuala Lumpur and Toronto's CN Tower are good examples here. Regardless of mortar's long history, the innovation potential of this time-honored material is by no means exhausted. Even though mortar is a traditional material, we would be wrong not to see it in a "high tech" light. Especially dry-mix mortar, modified with high-quality polymer binders, opens up broad innovative potential and a great many novel functions. Even small quantities of dispersible polymer powder suffice to imbue the mortar with new properties and qualities.

New solutions

Rising market demands were a major reason for new impulses in mortar technology. In the 1950s, mortar was still prepared on site from the individual raw materials. Germany's first post-war construction boom, however, soon required enhanced mixtures. Because "traditional" mortar comprising cement, sand and water adheres by way of mechanically interlocking with the substrate, it can only be used with porous substrates. That's why ordinary mortar was soon unable to meet growing demands of the construction sector.

As long ago as the 1950s, therefore, liquid polymer binders were added to mortar to enable better adhesion to a wide range of substrates. The drawback to this system, however, was that exactly the right amount of polymer binder had to be added to the mortar – at the construction site, which meant that metering errors were common.

In contrast, the invention of dispersible polymer powders was tantamount to revolutionizing the construction sector, because they made it possible to pre-mix mortars at the factory. On construction sites, these dry-mortar systems only needed to be stirred with water, simplifying matters enormously for the building industry and bringing economic advantages.

The birth of "VINNAPAS®"

The binder, marketed under the name VINNAPAS®, is a vinyl acetate/ethylene copolymer. VINNAPAS® polymer powders constitute what are known as spray-dried dispersions. The powder particles consist of a water soluble protective-colloid matrix in which the water-insoluble, dispersible particles are embedded. An anticaking agent prevents the powder particles from sticking together.

The name dispersible polymer powder is based on its ability to "redisperse" when water is added. As the mortar sets, flexible polymer bridges are formed between the brittle, mineral constituents of the mortar, thus greatly improving its adhesion to a wide range of substrates. The polymer bridges also increase the system's flexibility. In addition, it is possible to incorporate extra properties such as thixotropy, leveling, superplasticizing and hydrophobicity. While this construction solution has long been a matter of course in western industrialized countries, there is currently above average growth in demand both in southern and eastern European countries and on Arab and Asian markets.

Flexible handling and cost saving application

Today, VINNAPAS® products are chiefly used as tile adhesives. This is because the so-called thin-bed technique of laying tiles would not be possible without dispersible polymer powders, which enable the tiler to work much more cost effectively.

VINNAPAS® also outscores conventional mortars in ease and flexibility of handling, because it can stick to diverse substrates. For example, tilers used to face the horror scenario of bonding tiles to other tiles, wood, PVC, cement screed or fiberboard all in one building – which necessitated using a specific mortar for each substrate. This is no longer necessary, thanks to modern dispersible polymer powders.

Dispersible polymer powders are especially beneficial in skyscrapers, as they reduce the overall weight of such buildings and hence impact positively on the steel frame and foundations.

Enhanced thermal insulation

The useful properties of dispersible polymer powders are employed to advantage in other fields, too. An example here is EIFS (exterior insulation and finish systems) to insulate outside walls of residential buildings. Effective thermal insulation is the best way to save energy: whereas a non-insulated outside wall lets about 50 percent of the heat escape, additional thermal insulation will reduce this figure to between 10 and 15 percent. On account of its excellent insulating properties, expanded polystyrene board is chosen as insulating material. However, it has the disadvantage of not forming a stable bond with cement.

This drawback may be overcome with VINNAPAS® polymer powder. Three to four percent VINNAPAS® usually are enough to form a stable and permanent bond with the polystyrene board. This is equally true of the improved adhesion to all kinds of substrates, ranging from concrete, brick and old plaster coatings, to mineral wool.

Preventing water damage and seepage losses

Sealing slurries are based on VINNAPAS® polymer powders, as well. Because they are easy to use, the slurries are a sure form of protecting a large number of buildings from water damage. The slurries not only prevent damage caused by water ingress, but also help save water. Impregnated water channels and reservoirs, for example, prevent water loss, thus promoting the efficient and sustainable use of water.

Reflecting mega trends

Dispersible polymer powders have the potential to transcend current thinking by reflecting future megatrends. This applies as much to energy and water saving opportunities as it does to improving life conditions, as in interior design and lightweight construction. For example, efficient polymer-modified insulation can reduce uncomfortable drafts and inhibit unhealthy growth of mold, thereby greatly enhancing the indoor climate.

50 years of polymer powders

More than 50 years ago, in 1957, WACKER produced its first dispersible polymer powders in Burghausen in the course of running a series of tests. At that time, no one could guess the major impact WACKER's pioneering work would have on the construction sector as a whole. Today, we are curious to see how things will develop. After all, mortar is not just a material with a rich history, but, more importantly, one that continues to blaze trails.