The suitability of isothiazolone microemulsions as long term wood preservatives
B M Hegarty, Bing Yu, L E Leightley
Microemulsion formulations of 4,5 dichloro-2-n-octyl-4-isothiazolin-3-one were investigated to determine the leaching potential of these formulation types as well as their efficacy against decay fungi. These patented low leaching formulations exhibited good anti fungal efficacy in standard tests combined with minimal leaching of the active ingredient from the wood. The data suggests that the excellent long term efficacy ( > 10 yrs) recorded in field tests on solvent borne formulations can be repeated with these emulsion formulations. Active ingredient analysis show an excellent penetration and macrodistribution throughout the samples. Preliminary studies using various instrumental analytical techniques on active ingredient microdistribution at the cellular level show an even distribution throughout the cell wall layers. The data indicates that these microemulsion formulations are an excellent vehicle / carrier for solubilization of a water insoluble biocide, its transport and homogenous distribution into the wood without adversely effecting its permanence or efficacy in the wood during long term service.