Mortars for the Millions - Wacker Chemie AG

Mortars for the Millions

By constructing buildings, we are shaping tomorrow’s world. But the advanced building technologies we employ can only be realized with high-performance construction materials. Dry-mix mortars modified with WACKER polymers are used all around the globe in energy-saving insulation systems, flexible tile applications and self-leveling flooring compounds.

With around 25 million inhabitants, this metropolitan area is the largest urban agglomeration in China – and a center of the building boom. At present, every third newly erected building in the world is constructed in China.

The Estádio Beira-Rio is one of the most remarkable soccer arenas in South America. Located in the southern Brazilian city of Porto Alegre, it hosted one of the group stages of the 2014 World Cup, with teams competing to advance to the knockout phase. While that spectacular sports event is now over, it has left a swath of magnificent stadiums that were either built from scratch or modernized, such as the Estádio Beira-Rio, which was inaugurated in 1969 and was expanded prior to the 2014 World Cup. Proudly called the “Gigante da Beira-Rio” by the locals, this stadium, when not hosting World Cup games, is home to one of the best teams in the Brazilian Série A league. It can now seat more than 50,000 spectators – and its newly designed galleries are an architectural dream.

In the run-up to the 2014 World Cup, renovations that included the installation of a roof covering the entire stadium were carried out on the Estádio Beira-Rio, a 1960s construction located in the Brazilian city of Porto Alegre.

Such spectacular use of architectural concrete calls for suitably high-quality building execution down to the last detail, and getting the chemistry – or rather the construction chemicals – just right is essential. “The objective at Estádio Beira-Rio was to surface the bare concrete galleries with a fast-setting, smooth and highly abrasion-resistant flooring,” says Cristiane Fagundes, head of Sales and Marketing for Construction Polymers at WACKER in Brazil. “In collaboration with our customers, we achieved this with VINNAPAS®-modified self-leveling compounds.

“About 80 percent of the dry-mix mortar on the global market is still unmodified – we see substantial potential for growth here.”

Dr. Christoph Riemer Head of business unit Construction Polymers

Fast-Setting Flooring

In order to achieve a fast-setting, smooth and highly abrasion-resistant cover for the concrete floor of the galleries, VINNAPAS® modified self-leveling compounds were used.

Only with dispersible polymer powders can such self-leveling compounds greatly simplify all types of flooring work: irregularities can be smoothed out and a hard-wearing base created in a single operation. “That not only yields a better quality floor surface, but also improves its resilience and adhesion,” explains WACKER manager Fagundes. Additionally, less material is needed and drying times are shortened. The material is thinner and hardens faster - so the floor can be walked on sooner.

The smooth architectural concrete galleries of the Beira-Rio stadium are but one example of the many ways in which advanced building technologies benefit building execution and quality. As the various economies of the world become increasingly globalized, more and more buildings are springing up everywhere. Annual global construction activity is set to increase to 15 trillion US dollars by 2025, up by more than 70 percent. Especially in the emerging economies of Eastern Europe, Latin America and Asia, demand for high-quality construction chemicals is surging – it was these products that made modern construction technologies possible in the first place, one example being the use of polymeric binders to modify dry-mix mortars.

The global potential for WACKER’s VINNAPAS® product line is thus enormous: “About 80 percent of the dry-mix mortar on the global market is still unmodified,” says Dr. Christoph Riemer, head of the Construction Polymers Business Unit at WACKER. “In many regions, and particularly in growth markets, building specialists have only just begun to familiarize themselves with the benefits of polymer-modified dry-mix mortars. And consequently, we have optimized our global offerings.”

Not all Cement is the Same

To expand the market for innovative construction chemicals, WACKER has built up a network of Technical Centers around the world, including the one in South America. At WACKER POLYMERS in Brazil, Cristiane Fagundes and her twelve-strong team deal with queries related to mortars, and helping customers to enhance their existing recipes because the composition of mortars varies from region to region.

“The greatest regional difference concerns the various types of cement – unlike in Western Europe, where mainly pure Portland cement is used” explains Fagundes. The cements used in South America which are modified with blast furnace slags and pozzolan additives completely change the properties of ceramic tile adhesives, for example. So-called blast-furnace cement and ground-granulated blast-furnace slag are also used in western Europe especially where the modifying properties of these additives are required in the manufacture of concrete. For instance, when the cement has to be highly dense and durable in order to withstand the corrosive impact of road salt and acids. By contrast, manufacturers generally formulate dry-mix mortars for sophisticated construction markets with pure Portland cement. WACKER experts therefore first study the chemical and physical properties of the raw materials in their labs so that they can precisely tailor the polymer-modified dry-mix mortars to the applications and requirements specific to a particular region.

At the WACKER technical center in Brazil, an employee tests tile adhesives to check the tensile adhesive strength, which has been significantly improved with dispersible polymer powders.

Today, WACKER is a global market and technology leader in the field of polymeric binders based on vinyl acetate-ethylene (VAE) copolymers, which are sold around the world under the VINNAPAS® brand name. “Our binders are one of the chief ingredients of modern construction and tile adhesives, external thermal insulation composite systems (ETICS), self-leveling compounds and fillers, plasters and repair mortars,” says Andreas Collignon, head of Application Technology Construction Polymers at WACKER POLYMERS.

For ETICS, up to four percent VINNAPAS® in the mortar is enough to form a stable bond between the insulation board and substrate, for example. VINNAPAS® polymers provide an ideal and long-term solution, particularly for fixing difficult-to-bond materials to critical substrates.

Polymeric binders also revolutionized tile-laying by introducing the so-called thin-bed technique, in which the traditional cement mortar is replaced by a formulated tile adhesive that is spread quickly and easily over a large area. The tiles are then positioned and slid into place, creating a uniform adhesive bed that is just millimeters thick. Less material is consumed and tiles can be laid much faster. Possible applications are to be found all over a building, from tiled flooring through to roof insulation.

New dispersible polymer powders for tile adhesives

WACKER has developed a novel dispersible polymer powder for modifying cementitious and gypsum-based dry-mix mortars especially for tile adhesives. Based on a novel vinyl-chloride vinyl acetate-ethylene terpolymer, VINNAPAS® 8620 E ensures that tile adhesives adhere excellently to a broad range of different surfaces, including difficult ones such as fired tiles with high densities and natural-stone products – even after heat, water or freeze/thaw cycles. The dispersible polymer powder was specifically developed for the formulation of sophisticated tile adhesives of categories C2E or C2ES1 and C2ES2 as per EN 12004 that feature an extended open time and high flexibility. It thus offers users additional formulation reliability. With VINNAPAS® 8620 E in the formulation, it is thus even possible to reliably bond modern large-format or very thin tiles, as well as porcelain or natural-stone materials. Alongside exceptional product and processing properties, VINNAPAS® 8620 E also exhibits good environmental compatibility, because the product is free of plasticizing additives and thus makes it possible to formulate low-emission tile adhesives.

Benefits of the Modification

“Thin-bed systems, which include tile adhesives, afford polymer-modified dry-mix mortars the chance to show what they can do,” says Ole Mecker, head of the Eastern Europe, Middle East & Africa business team at WACKER in Burghausen. The polymers impart flexibility to the rather brittle mortar, enabling the hardened construction material to accommodate slight stresses between the substrate and tile. That boosts the level of adhesion between tile, mortar and substrate.

Polymer-modified dry-mix mortars also exhibit better water retention. This makes them easier to process and they do not dry out so quickly. The polymer in the hardened construction material improves the mechanical properties – the material can thus withstand load better and is more abrasion resistant. Finally, VINNAPAS® dispersible polymer powders also save on material: whereas conventional tiling requires more than ten kilograms of adhesive per square meter, the thin-bed technique requires only approx. one-third as much polymer-modified dry-mix mortar for the same area. It was these compelling advantages which persuaded the construction industry to adopt the very first dispersible powders, launched by WACKER in the 1960s, and they are winning over even more customers today.

Global demand for WACKER dispersible polymer powders rose by six percent in 2013 alone. Consequently, WACKER has been successively expanding capacity at all three of its production sites in Europe, Asia and the USA. In 2013, bottlenecks at Calvert City (Kentucky) were eliminated; the Nanjing plant in China is scheduled to double its current annual capacity by the end of 2014 and by the first half of 2015, there will be a new spray dryer that can produce some 50,000 tons of additional dispersible polymer powder in Burghausen.

Global Market Leader for Dispersible Polymer Powders

“We are far and away the world’s number one supplier of dispersible polymer powders,” stresses Dr. Christoph Riemer, head of Construction Polymers business unit at WACKER. “And our current expansion program gives a clear signal that we intend to keep our lead!”

The benefits of the VINNAPAS® dispersions are particularly apparent in modern, porcelain stoneware tiles fired at high temperatures and glass mosaics. “Because of the lack of pores, the mortar does not penetrate as much, and the crystals that form as it hardens are unable to interlock with the tile, which therefore does not grip as well as it might,” explains Klas Sorger, technical service manager for Construction Polymers at WACKER in Burghausen. The binders act like a glue between the mortar matrix and the tile. When the cement in the mortar sets, the polymer particles fuse together, forming so-called resin domains that provide the necessary adhesion.

Practical Powders

By inventing dispersible polymer powders, WACKER changed the face of the construction industry. Until then, mortar had still been mixed manually on site – occasional mixing errors were inevitable. Then the products had to be spread on in thick layers, wasting time and material. VINNAPAS® dispersible polymer powders enable the production of premixed dry-mix mortars that only need to be mixed with water on site. The binders, which are based on vinyl acetate and ethylene, are produced by spray drying dispersions. And VINNAPAS® offers further benefits providing the mortars with precisely the right technical properties, including improved processability, excellent adhesion to all substrates, reduced material consumption, increased flexibility and better weathering resistance. On site, there is no other way to prepare specialty mortars of this kind which are tailored to modern construction techniques.

But improved adhesion is not the only advantage. Flexibility of the mortar, which is an otherwise naturally brittle material, plays an important role in thin-bed systems: after all, walls and floors are continually being stressed by temperature fluctuations, the building drying out and chemical changes in the material – and the polymer matrix helps them to better accommodate these.

Consumer Demands Rise With Increasing Income

Yet it is not only the excellent properties that favor the use of vinyl acetate-ethylene-based binders in dry-mix mortars. Customers’ wishes also play a role. “Here in Brazil, demand for better materials is growing partly because per capita income is rising,” says Cristiane Fagundes. “Demand for porcelain stoneware tiles, for example, has increased by 20 percent, and you need polymer-modified mortars to lay them properly.” A further challenge in South America is the different regional climates. In Chile and northeastern Brazil, the weather is very dry, whereas in central, tropical regions, it is very warm and humid. And in the south of the continent, it can even be very cold and windy. All this affects the drying time and thus the ease of working with the mortar. “We are therefore devising different recipes for each region so that the material is optimally adapted to local conditions,” says Fagundes.

Regional climatic variations also pose a challenge for Mohammed Sanaobar, a WACKER colleague in Dubai who is responsible for the vast region of the Middle East, ranging from Pakistan to Mauritania in North Africa and the African continent – some 25 countries in total.

Polymers Extend Open Time

Micrograph of the the bonding course between VINNAPAS®-modified dry-mix mortar (left) and ceramic tiles (right).

“In the desert regions of Africa and Arabia, the temperatures sometimes reach 50 °C,” explains Sanaobar. This causes the mortar to dry out very quickly. Deploying dispersible polymer powders would prolong the pot life of the dry-mix mortar considerably, by 10 to 15 minutes, while at the same time reducing the formulation costs for many customers.

In Europe, by contrast, there are different priorities due to the different construction methods. Cost pressures here are high, too, but so are the wages, and machinery is widely used. The building professionals in the developed industrial nations figure that the way to lower the costs there is to have fewer working steps. So, the approach is to devise building materials and additives that make products easier to use on site. Premixed polymer-modified dry-mix mortars meet this need, because they do not have to be mixed on the building site. That saves time and rules out the risk of mistakes during preparation. The more unskilled or semiskilled workers there are working on the site, the greater that risk is.

Every third new building is constructed in China

One of the most interesting markets for construction chemicals is China, whose mega-cities are buzzing with more construction activity than anywhere else in the world. A study by the European Center for Small and Medium-Sized Enterprises shows that China now constructs roughly one-third of the world’s new buildings. The country consumes around 55 percent of world cement production, with living space alone increasing annually by 1.8 billion square meters.

Promising Market Environment

VINNAPAS® dispersible polymer powders Classes L and F

Class L VINNAPAS® dispersible polymer powders improve both the mechanical and flow properties of building materials. Used together with casein and synthetic superplasticizers they produce very smooth, flawless surfaces. They also reduce surface bleeding and sedimentation. Class F VINNAPAS® dispersible polymer powders function as both binders and superplasticizers in self-leveling flooring compounds. This allows the compound to be applied efficiently and economically with a grout pump. Furthermore, Class F VINNAPAS® dispersible polymer powders determine specific flow properties (rheology) of the self-leveling compounds, depending on the scope of application and type of delivery required. Class L and F VINNAPAS® products at the correct dosage fulfill various European eco-labels such as the Blue Angel and EMICODE EC1 PLUS.

Dr. Thomas Bastelberger, a research chemist at WACKER POLYMERS, has already developed new dry-mix mortars aimed specifically at the Chinese market and speaks from experience: “At the moment in China, the overriding consideration is that the building materials should be inexpensive.” Labor costs are low and so it is virtually immaterial if construction falls behind schedule. However, Dr. Bastelberger believes that China offers enormous potential for polymer-modified dry-mix mortars – and not just because of the frenetic building activity. “Ceramic and porcelain tiles are extremely popular in China.” China is the world’s largest producer and consumer of tiles, and so it ought to be the perfect market for our products.”

The WACKER experts still need to do some educational work in some regions, though, before the highly favorable market conditions will translate into the expected demand. “The biggest hurdle is a lack of regulation. The fact that there are no standards often means there is no legal pressure to use any high-quality products that will ensure durability,” says Sanaobar, head of the WACKER Technical Center in Dubai.

To raise quality awareness for mortar in the various regions and to encourage the development of building codes, WACKER is collaborating with universities and research institutions, such as Dubai Central Laboratory at the Dubai municipality. “Through our efforts, we are helping to improve building codes in these regions and in so doing are indirectly boosting demand for WACKER dispersible polymer powders,” says Ole Mecker head of the Eastern Europe, Middle East & Africa business team at WACKER, by way of explanation.

Easy to Process

At the technical center in Moscow, lab technicians examine the flow properties of polymer-modified, self-leveling floor and smoothing compounds.

In China, too, more work will be needed before polymer-modified dry-mix mortars become widely established. The advantages of ready-to-use mixes, such as consistent quality and quick and easy processing, are still a side-show for some developers, given the low labor costs and lack of warranty claims. “Although the Chinese government is trying to establish standards, it is falling short in terms of enforcing compliance and conducting inspections,” says Lars Nordblom head of Greater China Construction Polymers business team, who was seconded by WACKER to Shanghai where he has driven forward the expansion of Sales and Application Technology at Construction Polymers. The WACKER chemists therefore decided to rely entirely on their applications know-how and consulting expertise. They maintain close contacts with the mortar manufacturers, explaining the various systems and advantages to them. “Unlike the Europeans, the Chinese are very keen to experiment, and their unconventional approach quite often comes up trumps,” says Lars Nordblom.

A lab technician at the technical center in Brazil experiments with polymer-modified tile adhesive.

Despite regional differences, there are a number of similarities throughout the construction industry, whether in developing, emerging, or industrialized nations. Competition is generally fierce, cost pressures are high and local companies maintain extensive networks. “That is why it is important for us to develop a customized solution that meets the local needs of each market and also delivers an attractive price/performance ratio,” explains WACKER manager Christoph Riemer.

There is still a lot of potential in the dry-mix mortar market – and the WACKER team is well positioned to enhance construction technology all around the world.

“It is important to develop solutions tailored to local needs for every market.”

Dr. Christoph Riemer head of Construction Polymers business unit at WACKER