Exterior-use coatings

Exterior-use coatings must be weather-resistant they must adhere to a wide range of substrates and retain their gloss and shade fastness for a number of years. Suitable binders and pigments must therefore be chosen [11.33]. 

The most important requirements and properties of exterior-use coatings on mineral substrates are the water permeability to water and water vapor and protection against carbon dioxide. 

Aqueous systems such as silicate paints and vinyl or acrylic emulsion paints are suitable for opaque and semitransparent coatings. Silicate paints have a high degree of hardness and good permeability to water vapor and gas. Evaporation of moisture is not hindered, peeling and flaking are therefore avoided. 

The most important properties of exterior-use emulsion paints are their rheology (good application) and the water and water vapor permeability which influences the moisture balance of the substrate and thus the durability and protection of the substrate. 

Solventborne paints are based on synthetic resins (e.g., acrylate styrene copolymers) which are soluble in aliphatic and/or aromatic hydrocarbons. The properties of these coatings are chiefly determined by the nature and proportion of the monomers. 

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