Extending the Life of Dry-Film Coatings by Selecting the Right Preservative Systems

摘要

How do you effectively preserve an exterior paint film to last? What are the chemical properties needed for the fungicides to control and inhibit fungal growth? In today’s coatings market,consumers are looking for an exterior paint that lasts years without biodeterioration.This is very challenging,as exterior paint films are exposed to outdoor environmental conditions containing high levels of microorganisms and nutrients for the microorganisms.Considering this,an exterior dry-film preservation system for coatings needs to have the following characteristics for microbiological protection: broad spectrum fungicide efficacy,good initial and long-term protection,and chemical stability in the wet and dry film stages.In addition,the dry-film fungicide must not adversely affect the finished paint film in terms of color change or increase the drying time.One powerful and widely used fungicide for dry-film protection is iodopropynylbutylcarbamate(IPBC)with efficacy against blue stain strains and mold growth on paint surfaces.Yet,IPBC has disadvantages like possible yellowing in the dried paint film and a medium-to-high leaching potential which may lead to shorter dried paint film life spans.To overcome these disadvantages,combining individual fungicide actives usually provides a better toxicity profile,lower dosages,longer finished product shelf life,and compensates for weaknesses or gaps of individual fungicide actives.In several matrixes,propiconazole has been identified as a perfect active partner for IPBC.The combination was tested in different binders,on multiple substrates,and in multiple locations worldwide.In this paper,we look at the benefits of the combination of IPBC and propiconazole and other active ingredients in both laboratory and exterior weathering studies.