Oleochemicals

Important additives for building protection

Abb. 1 Quadratwurzel-Zeitgesetz für die Wasseradsorption von Baustoffen.

Fig. 2 Categorization of soaps and metallic soaps.

Fig. 3 Influence of fatty acid on the water repellance.

Fig. 4 Direct and indirect hydrophobation.

Fig. 5 Dosage of some water repellent agents in standard renders (see Table 2).

Fig. 6 Dosage of zinc stearate in standard renders (see Table 2).

Fig. 7 Sodium oleate and modified zinc stearate in standard render (see Table 2).

Fig. 8 Influence of calcium stearate concentration on the hydrophobic effect of concrete.

Fig. 9 Influence of mixing intensity of dry mortar on water repellence.

Fig. 10 Long-term stability of the water repellent treatment with the help of metallic soaps.

Hydrophobic surfaces inhibit a water absorption

Oleochemical raw materials, namely metallic soaps and sodium oleate are characterized by a beneficial cost/performance ratio. The water absorption coefficient (w) in water resistant plasters has to be below 0.5 kg/m²h0.5. To achieve this, metallic soaps are widely used. An essential criterion in this application is the quality of stearate. Mainly precipitate stearates, with their high specific surface, perform well. While using sodium oleate during the setting of the render, a reaction with calcium ions in the cement or limestone takes place and the oleates are transformed to hydrophobic metallic soaps. The interaction with other raw materials in the plaster formulation is much more pronounced. Product mixtures of stearates and oleates could be an answer to this problem.

A natural decline process occurs in almost all things we perceive in our environment. Wherever possible, human beings try to protect ventures, undertakings against this process. This protection can also be applied to buildings, because they are clearly visible signs of human creativity and they decline when they are subjected to the adverse affects of environment. Water is the most common cause of serious damage. It is responsible for the transport of harmful substances like salts, promotion of the growth of micro-organisms and frost damage in cold periods. Also, heat transition is directly...