Mold & Mildew - Control Studies
For years, mercurial paint preservatives have set the standards regarding performance against mildew growth.
However, in 1995, all US EPA registrations were cancelled for toxicity & environmental concerns.
A four-year exposure study performed by Merck compared three different types of coatings & mildew resistance. The study also compared various levels of Stay-Clean I/E with phenyl mercury compounds.
Paint 1: Control: Non chalking 25% long oil alkyd modified polyvinyl acetate paint. The paint had two coats. Self-primed on white pine siding. The control showed light mildew at six months and moderate to heavy after 15-18 months.
With Additives: Stay-Clean I/E and the phenyl mercury compound exhibit perfect mildew control during the first 12—15 months with trace mold remaining 2.5 years of exposure.
Results: Both Stay-Clean I/E and phenyl mercury showed good mildew control.
Paint 2: Control: Non-chalking 20% long oil alkyd acrylic paint. Two coats self-primed on white pine. After three years — heavy mold developed.
With Additives: Stay-Clean I/E exhibited perfect mildew control for more than three years. Trace mildew was noted after39 months exposure. Light mildew growth on the phenyl mercury-treated paint was observed at 18-months.
Results: Stay-Clean I/E showed the same good mildew control as phenyl mercury and was superior in all other exposures. Paint 3: Control: Non chalking 15% long oil alkyd acrylic paint. One coat top coat over 15% alkyd paint were applied to edge-grain cedar. Control topcoat was also tested over primers protected with phenyl mercury and Stay-Clean I/E.
Results: Better mold control was observed with Stay-Clean I/E. Equivalent mildew control was observed with primers and topcoats treated with phenyl mercury and Stay-Clean I/E.
Test Organism |
MIC (A.I.,ppm) |
Yeast and Fungi |
|
Alternaria candidus |
5.0 |
Alternaria chevalier |
10.0 |
Aspergillus fumigarus |
8.0 |
Aspergillus niger |
10.0 |
Cladosporium sp |
5.0 |
Colletotrichum lindemuthianum |
10.0 |
Dacrylium dendroides |
0.4 |
Diplodia natalensis |
20.0 |
Fusorium roseum |
1.0 |
Microsporum audouini |
7.0 |
Neurospora sitophilia |
5.0 |
Pullularia pullulans |
0.2 |
Stadhibotris sp |
10.0 |
Tridhoderma viride |
10.0 |
Ustilago zeae |
8.0 |
Verticillium albo-atrum |
1.0 |