Adhesives & Sealants News
Evonik introduces powerful, environmentally friendly shrinkage reducers
Not only do SITREN® additives offer special environmental advantages—in many cases they perform better than previous systems as well.
New SITREN® shrinkage reducers are notable for their extremely low concentration of volatile organic compounds (VOCs), making them particularly well suited for shrinkage-reducing cement formulations used in building interiors. Available in liquid or powder form, these additives meet the strict requirements of many environmental certification standards—regardless of the concentration used. The new products, which were developed in close collaboration with the additives industry, perform impressively well too. As extensive tests on various types of mortar and concrete have shown, these shrinkage reducers are significantly more effective than classic systems in virtually any formulation.
Shrinkage is a key challenge of many mineral-based systems used in construction. Moisture release and chemical reactions within the building material result in an undesirable reduction in volume during the drying process. Various approaches can been taken to control the phenomenon, such as the use of cement with less shrinkage or the addition of components that will cause the mixture to expand. These not only pose a technical challenge, however—they also drive up the cost of the formulation.
For some time now, manufacturers have responded by using organic shrinkage reducers. These surface active substances affect how the water contained in the construction material interacts with other components of the formulation, thereby reducing the tendency to shrink. Typically, however, the proportion of volatile organic compounds in these substances is high. The resulting health concerns have caused their use to come under increasingly critical scrutiny, and the concentrations at which they can be used are strictly limited in order to minimize VOC emissions.