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Anti-aging for facades
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The Info Box
The ABC of dispersion paints
A dispersion is a homogeneous mixture of substances that are not soluble in each other. A dispersion paint has at least three components. Water – and in rare cases volatile solvents – serves as a liquid dispersing agent in which large amounts of tiny solid particles are suspended: pigments are incorporated to make the paint either white or colored. Binders accounting for about half of the weight of the liquid paint become tacky on drying and bond the pigment particles both together and with the substrate. They are also critical factors for producing the mechanical properties of the coatings.
Synthetic resin dispersions are now by far the most widely used type of wall and facade coating. As binders they contain synthetic resins, products of hydrocarbon based organic chemistry which are hard or viscous depending on the temperature. The resulting elasticity of the finished coating is also their weak point: high temperatures soften the thermoplastic material and make it tacky.
Silicate paints, on the other hand, have as their binder water glass, an inorganic compound of silicon and oxygen. Silicate coatings can only be applied directly onto lime or cement plaster with which they combine chemically to produce a glass-like layer which is waterproof and extremely hard, but also brittle. Silicate paints are also corrosive and difficult to apply.
As the first nanocomposite coating to contain COL.9, Herbol-Symbiotec combines the advantages of synthetic resin and silicate dispersions: the organic content of acrylic resin provides sufficient flexibility; because of the silicate nanoparticles homogeneously embedded in the resin, however, it is much harder than a purely synthetic resin coating. The nanostructures that form on the surface reinforce the hydrophilic, water attracting property of the silicate with the result that dirt is washed off more easily.
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