Human behavior has caused a great impact on the world; it has taken us time to understand the repercussions and the environmental accidents that have seriously compromised our own future. Chemical weapons, insecticides, fertilizers, industrial effluents, paints and organic solvents have damaged the health of the planet and its inhabitants to the point of contaminating even the most remote places.
In the eighties, due to several environmental scandals, different scientific publications, etc., prompted the need for a new environmentally friendly and transparent chemistry. Conventional coatings contain derived synthetic products from the petrochemical industry that can harm our health and the environment. The danger resides in the heavy metals such as lead, cadmium, mercury, etc., and in VOCs such as xylene, toluene, phenols and formaldehydes, which are emitted by paints and varnishes when applied, or while they dry.
The challenges currently faced by the coatings industry are not just to reduce cost and improve performance but also to fulfill strict legal requirements. In an American technical magazine the technical director of a major national paint company recently reported that his staff spends nearly 40% of its time reformulating their paint in order to meet increasingly stringent VOC regulation. Forty percent of his staff’s time is a lot of time, and is robbing energy and efforts that could be devoted elsewhere, such as toward new developments.
The technical director was expressing a universal phenomenon in the paint industry. Large amounts of manpower are focused on correcting current formulations to new eco-green developments: replacing products containing hexavalent chromium or lead, among other heavy metals, and reducing or eliminating VOCs. This also avoids any undesired labelling that may be associated with toxicity in general.
In terms of corrosion inhibitors, some of the most effective and widely used anticorrosive pigments such as red lead (PbO4), lead silica-chromate (4 (PbCrO4 · PbO) +3 (SiO2 · 4 PbO)), zinc chromate (ZnCrO4), zinc tetraoxychromate (ZnCrO4 · 4 Zn(OH)2), and strontium chromate (SrCrO4), have been and continue to be under heavy scrutiny due to the hazards posed to humans and the environment. Lead compounds are deemed toxic, zinc and strontium chromate are classified as carcinogenic and most recently, according to the EU Directive 004/73/CE, zinc phosphate has been determined to be a danger to the aquatic media.
In general, the latest global trend is to design coatings that comply with the environmental regulations that now exist. These “Eco-Friendly” or “Green” coating systems contain only non-toxic, non-reportable raw materials to ensure no hazard to humans and the environment. The industry has found it very difficult to obtain the same level of performance with the eco-friendly systems as compared to the non-compliant systems.