A Binder Connects the World

Over a span of 75 years, the pioneering spirit of the very first WACKER chemists has evolved into a global brand: VINNAPAS® binders today are at home in numerous industrial sectors the world over. They bind colorful pigments into spreadable paints and coatings, form the basis for adhesives and ensure that plasters adhere to facades and textile layers stick to carpet backings. New application fields are still emerging to this day.

Without binders, the world would lose its hold. In the construction industry, VINNAPAS® brand polymer dispersions and dispersible polymer powders ensure that plaster bonds reliably to brickwork and concrete, is easier to work with and, depending on individual requirements, is water repellent as well. The packaging industry uses VINNAPAS® dispersions in the formulation of plasticizer-free adhesives, for example. These kinds of adhesives are used in food packaging, to ensure that no undesired substances get mixed in with the pasta or the breakfast cereal. The paint industry in turn combines VINNAPAS® dispersions and colorful pigments to formulate readily spreadable and printable interior and exterior paints, as well as surface and paper coatings. Carpet manufacturers need VINNAPAS® binders to hold the textile layer and carpet backing together. As part of table napkins, wet wipes and feminine hygiene products, VINNAPAS® dispersions improve the special properties of these nonwovens, such as softness and absorbency.

It All Began with an Emulsion

The polymerization process used at WACKER, which, for the first time, made it possible to adjust the polymer emulsion viscosity to particular requirements, has been patented since April 1, 1938. Industrial-scale production of polyvinyl acetate dispersions commenced at the same time.

The success story of WACKER’s innovative binders now spans 75 years. In November 1937, the Burghausen site began producing VINNAPAS® Emulsion H60 – as it was then known – which is still produced today, only in a slightly modified version. The polymerization process used at WACKER – which, for the first time, made it possible to adjust the polymer emulsion’s viscosity as required – has been patented since April 1, 1938. VINNAPAS® H60 has been manufactured on an industrial scale ever since. In the beginning, around 25 metric tons of this dispersion left the site every month. WACKER chemist Dr. Herbert Berg developed the process, along with Herbert Mader and Martin Doriat. VINNAPAS® Emulsion H60, which was used in the formulation of wood glue, quickly became a bestseller. Wood glue is still a standard application of the VINNAPAS® product family, which has become very large and versatile. Just two short years after production started, WACKER was making over 40 metric tons of H60 dispersion each month. This grade was a so-called homopolymer, consisting of an aqueous polyvinyl acetate dispersion with a solids content of 60 percent (hence the name), which was stabilized by the addition of polyvinyl alcohol as a protective colloid. WACKER had already gathered experience in the manufacture of polyvinyl acetate prior to developing the polymerization process that it patented in 1938. In 1924, Dr. Willy O. Herrmann created the technological foundation at the Consortium, the company’s central research facility in Munich, by developing a procedure for the manufacture of vinyl acetate monomer by addition of acetic acid to acetylene. Production reports of that time soon referred to this liquid monomer as “Vinna” – a first hint at what would later become the VINNAPAS® brand name.

Initial Attempts with Sunlight

But polymerization was still a challenge in those halcyon early years of plastics chemistry, when chemists lacked the processes that would enable targeted manufacturing of polymers. Since 1912, however, it had been known from the work of Fritz Klatte, a chemist from Frankfurt, that liquid vinyl acetate tends to spontaneously polymerize under the influence of light. That’s why, in the beginning, WACKER scientists had the monomer filled into ten-liter glass bottles, which were then exposed to the sun until solid polyvinyl acetate resin had formed in them. The bottles then had to be broken to get at their contents. One year later, in 1925, the discovery of peroxides provided a catalyst for accelerating the polymerization process. Shortly thereafter, the Consortium was granted a comprehensive utility patent for polyvinyl acetate-based binders and adhesives that are sold under the VINNAPAS® trademark. Following the breakthrough with the polymerization process that was patented in 1938, WACKER chemists rapidly developed the binder further. They mixed plasticizer additives into the VINNAPAS® homopolymer dispersions, for example, to create elastic bonds suitable for paper applications. The additive also enhanced the water resistance of distemper. By 1943, production of VINNAPAS® dispersions at Burghausen had reached 2,600 metric tons.

Emulsion Paint Becomes the Standard

Workers at the West plant's VINNAPAS® facility in the mid-1950s.

After WWII, production was initially stopped and subsequently resumed in September 1945. The so-called plasticized VINNAPAS® dispersions – to which a plasticizer had been added – that had been developed at the end of the 1930s, became popular with the general public in the postwar years. It wasn’t long before polyvinyl acetate replaced glue as the binder and emulsion paint established itself as the standard product – all around the world today.

During the years of West Germany's economic miracle – the 1950s and 1960s – the new binders developed into a platform for ever more innovations. WACKER scientists experimented with the chemical structure of the polymer chains, inserted so-called copolymers and thus created new properties. In 1955, the 50/25 VL grade – in which vinyl laurate acted as the monomer, without plasticizing additives in the resulting copolymer – was launched on the market. This molecular building block rendered the dispersion film plastic; in addition, the plasticizer could now no longer evaporate. The advantage was that the dispersion film retained its high flexibility over the long term and did not become brittle over time. As a result, the product was ideal for wallpaper adhesives, for example, improving their wet-bonding and dry strength.

Terpolymer dispersions with vinyl chloride joined the product line in 1962, and in 1964 came the true quantum leap: VINNAPAS® EP1 – the first water-based copolymer dispersion based on vinyl acetate and ethylene – was launched on its road to success, initially in the adhesives market. Copolymerization with ethylene immediately expanded VINNAPAS® dispersions’ application range, because the ethylene component provided the polymer chain with greater flexibility and also made plasticizers redundant in later end-product formulations.

Bottles of acetic acid in an experimental laboratory at the Consortium, WACKER’s central research facility in Munich, around 1930. In those days, vinyl acetate monomer was still made by reacting acetic acid with acetylene.

Several years earlier, VINNAPAS® had made another leap forward: polymer binders in the shape of so-called dispersible polymer powders. Here, a spray method was used to remove the water from special dispersions, which made it possible to store and transport the polymer binder. In the development of these powders, WACKER chemist Dr. Max Ivanovits was inspired by the concept of instant coffee – and so he built a miniature spray-drying test facility. His line of thinking was that if the Group could succeed in preparing its dispersions in the form of dispersible polymer powders, the market for polymeric binders would explode. Following the rapid success of Ivanovits' tests, industrial-scale production commenced at Burghausen on July 2, 1957, when the first 13.2 metric tons of free-flowing dispersible polymer powder emerged from a PVC dryer. The individual powder particles consist of a water-soluble protective-colloid matrix in which the water-insoluble polymer particles are embedded. The powder particles are prevented from sticking together by a so-called anti-blocking agent.

In the beginning, the production process required a lot of optimization, especially with regard to the spray drying. However, probably the biggest obstacle at that time was that, in the beginning, there was no market for dispersible polymer powder. That changed rapidly in the 1960s, as construction became increasingly industrialized and architects tried out new structures and building methods. The redesign of VINNAPAS® binders on the basis vinyl acetate-ethylene copolymers and the development of the spray-dryer process came at just the right time.

Since the 1970s oil crisis, energy conservation has been a particular challenge for the construction industry. And in 1977, the first regulation on energy-saving thermal insulation of buildings took effect in Germany requiring improvements such as double-glazing or similar in new buildings. This regulation has been amended many times, with ever more stringent provisions. As buildings were made fit in terms of energy efficiency and increasingly equipped with EIFS/ETICS since the late 1980s, higher-performance mortars became necessary. Chemists and applications engineers at WACKER POLYMERS were faced with the challenge of developing VINNAPAS® products for these systems. Polystyrene panels used to thermally insulate buildings’ facades have the disadvantage that they do not form stable bonds with pure cement mortars. However, even minor additions in the region of 4 percent of VINNAPAS® polymer powder to adhesive mortar are sufficient to form a stable, permanent bond between the polystyrene board and the mortar.

Ongoing Development

VINNAPAS® dispersions being filled into drums at the West site in 1959.

Fruitful collaborations with our customers was the key to success, which is why WACKER experts have a tradition of collaborating closely with their industrial partners in the development of their products. It’s the only way of optimally tailoring the properties of VINNAPAS® to market requirements. This is how, in the end, polymer-modified dry-mix mortars could fulfill the requirements of the modern construction industry in the early 1960s. The advantages include consistent quality, improved adhesion to all substrates, increased flexibility and simple, safe processing – in-plant polymer modification practically eliminates mixing errors on the construction site.

In the 1960s, the groundwork was also laid for today’s biggest application area of VINNAPAS® products: tile adhesives. Dispersible polymer powders made the so-called thin-bed technique possible, allowing tilers to work considerably more economically. Furthermore, they gave rise to self-leveling flooring compounds – a great simplification for flooring work: one work step was enough to smooth out any unevenness and create a homogeneous, strong base for tiling and other floor coverings. The advantages: reduced material consumption, faster drying, better surface quality and durability of the final product – and secure bonding to a wide variety of surfaces.

Globally Successful Product

The wide range of favorable properties turned the VINNAPAS® product family into a real globetrotter. In 1998, together with US partner company Air Products and Chemicals (AP), WACKER founded the two joint ventures Wacker Polymer Systems and Air Products Polymers, one of which was responsible for powders and the other for dispersions – and laid the foundation for worldwide success. A decade later, in 2008, WACKER took over its partner’s shares in the two joint ventures and thus expanded its international position as market leader for VAE dispersions and dispersible polymer powders. When it comes to VAE dispersions and dispersible polymer powders, WACKER can draw on an integrated supply chain in three key regions: the Americas, Asia and Europe. In an integrated process developed over a period of over 75 years, WACKER POLYMERS uses ethylene and acetic acid to produce vinyl acetate and then vinyl acetate-ethylene. Thanks to the integrated production system, all byproducts are reused intelligently and fed back into the production loop. The VAE operations and spray-drying facilities at the Burghausen and Nanjing (China), production sites are some of the largest in the world, and the WACKER POLYMERS division also operates major production facilities at WACKER sites in Cologne, Calvert City (Kentucky, USA), and Ulsan (South Korea). Last year saw the division’s sales of dispersions and dispersible polymer powders based on polyvinyl acetate and vinyl acetate copolymers cross the €1 billion threshold for the first time – a further milestone of the 75-year VINNAPAS® success story.

The global presence also increased the importance of local customer support. WACKER maintains a global network of technical centers. The most recent of these to open was the technical center in Mexico City, with others located in Burghausen, Seoul, Singapore, Mumbai, Moscow, Dubai, Shanghai, Beijing, São Paulo and Allentown. At the technical centers, WACKER POLYMERS experts apply their region-specific expertise in close collaboration with local customers to find customized solutions to meet their needs. In this way, VINNAPAS® products can be tailored to local industry requirements and climate-specific differences – particularly relevant for the construction sector – as well as national standards, regulations and building traditions.

The Group’s in-house WACKER ACADEMY facilities are responsible for providing corresponding expertise via customer training sessions and distributor seminars. The Group maintains these facilities at a dozen sites on three continents. The WACKER ACADEMY trainers cooperate closely with the experts at the technical centers. Bundling sales, applications laboratories and the training center under one roof fosters close teamwork between the sales and development teams and optimizes customer support in the region.

Through 75 years of ongoing development, the pioneering spirit of the very first WACKER chemists has evolved into a global brand: VINNAPAS® has today become a technology platform known across many industrial sectors. VINNAPAS® provides adhesives, paints, mortars, carpets, nonwovens, technical textiles and many other products with exactly the properties they need in their current application area. Demands on materials of the future are increasing: not only must the materials meet ever more specific requirements, they must also become more environmentally and climate friendly, energy efficient and sustainable. Here, WACKER’s VINNAPAS® binders are key components without which many innovations would not even be possible – yesterday, today and certainly in the future, too.