Reducing the Environmental Impact of Effective Dry-Film Biocides

John Gillatt*, Thor Specialities (UK) Limited, UK (johng@thor.uk.com )

Of the three main groups of microorganisms that can infect paints and similar surface coatings it is fungi and algae that are especially problematic after the material has been applied. Fungi cause surface disfigurement and actual degradation, whilst algae also detract from the product’s aesthetic qualities as well as retaining high levels of moisture with resultant damage.
Exterior surfaces can become infected with both types of organisms and broad-spectrum antifungal/antialgal biocides have been developed to prevent such growths. However, changing EU legislation relating to the labelling of such biocides, pressure from environmental and consumer groups and revised regulations concerning insulation of buildings have placed greater demands on biocides and have created a need for new products with novel properties.

Biocidal active agents can be protected against UV degradation, alkaline attack and leaching whilst, at the same time, enabling products with reduced toxicity, environmental impact and less tendency to cause discolouration of the finished coating.