Leaching, paints/coatings

In the U.S., the most common construction material in terms of exposed surface area is comprised of various types of painted surfaces, especially painted wood, which is found to some extent on most residential buildings. The sensitivity of paints depends on their constituents research has shown that acid-soluble components such as CaC03 or ZnO may be selectively leached out from the coating (33). To our knowledge, the effects of such leaching on coating service lives have not yet been quantified. 

Leaching (1796) v. The process of the extraction of a component from a solid material by treating the material with a solvent that dissolves the component of interest but not the remaining principle material. Natural leaching occurs when rain water dissolves soluble salts from soil. Some components of a paint coating leach from the dried film after application to a substrate when exposed to rain or when immersed in water. 

Toxic It is harmful or fatal when ingested or absorbed, or it leaches toxic chemicals into the soil or groundwater when disposed of on land, i.e., wastes containing cadmium, lead, or mercury such as adhesives, paints, coatings, polishes, varnishes, thinners, and treated woods. 

One of the benefits of chromating is that the mixed (chromium/substrate metal) oxide coating provides better corrosion resistance than the natural substrate metal oxide alone. Additional corrosion protection is provided 1 chromate ions entrapped in the coating. These ions are readily leached from the coating and act as corrosion inhibitors. The ability of any CCC to improve the adhesion of paint coatings may be related to its cellular microstructure (Biestek and Weber 1976), which provides a base with more attachment points. 

Efficient protection in coatings exposed to increased temperatures and leaching environment was imparted with copolymers end-capped with O-alkylhydroxyl-amines [288] or with siloxane based HAS 36 [150]. Gloss of the acrylic or polyester topcoat is conserved. The ability of 36 to form bonds with aluminium powder or mica increases its performance in paints. 

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