Study On Preparation And Properties Of Triazole Wood Preservatives

Triazole fungicides are low toxic to human and animals, safe and environmental friendly,and effective against basidiomycetes and some wood-stain fungi, triazole fungicides have greatpotential for application in the wood protection. However, The solubility of triazoles in water isvery low and organic solvent-triazole formulations have high cost, emmission of volatileorganic compounds (VOC) and other problems. Therefore, the preparation and properties ofwater-soluble triazole formulations were conducted in the study.In order to prepare water-soluble triazole wood preservatives, the effective triazolecompounds, solvents and emulsifiers were selected firstly, as well as the best ratio of the activeingredients of the triazole formulations were determined. Then the leaching properties ofdifferent kinds of triazole and different kinds of emulsifiers were deterimined and compared forimproving the leaching rate of the formulations. Finally, the corrosion rate, the resistancesagainst decay, mold and sapstain fungi by triazole formulations were evaluated. The mainfindings and conclusions are summarized as follows.1) In addition to propiconazole (PPZ), tebuconazole (TEB) and cyproconazole (CY)which have been used in wood preservatives, the hexaconazole (Hex), epoxiconazole (Epo)and triadimenol (Tri) had better inhibitory effects against decay fungi, and the effects wereequivalent to CY. Therefore, these triazoles could be used as active ingredients of noveltriazole wood preservatives. For the mixture of triazole/copper (Cu) formulations, the optimalratio: Cu/Hex was99:1~70:1, Cu/Epo was about124:1~70:1, Cu/Tri was49:1~32:1. Whenused alone, some triazoles had poor inhibitory effect against sapstain fungi except PPZ, TEBand CY.2) Several kinds of water-soluble triazole formulations were prepared successfully,including PPZ, TEB, CY, Hex and Tri. The appropriate emulsifiers were including a kind ofcationic surfactant (CE-2) and the mixture of CE-2with lauryl dimethyl amine oxide (OA-12) or lauryl dihydroxyethyl amine oxide (OAE-12) or CE-4. The optimum amount of emulsifierswas0.9times of PPZ/TEB.3) The leachabilities of different triazoles and different emusfers were tested. the fixationrates of PPZ and Hex were higher and more than70%. The fixation rate of TEB was littlelower than PPZ and Hex. The fixation rate of CY in treated wood was between60%to70%and that of Tri was less than60%at the highest retention. The leach resistances of the samekind of triazole in different foumulations were equal. After compounding with Cu or CBZ, Theleach resistances of triazole were improved with the fixation rate of more than80%or90%. Inaddition, the fixation rate of Cu in wood treated with the mixtures of Cu/triazole was morethan90%and that of CBZ was about70%. The fixation rates of triazole and CBZ in treatedwood could be improved effectively through brushing hydrophobic agent on wood surface.4) The method for determining corrosion rates of metals in contact with treating solutionwas used to evaluate the corrosiveness of triazole formulations. The corrosion rates of Q235Asteel and red copper in the compound preservative containing Cu, PPZ and TEB (CuPT) wereboth lower than in ACQ, especially for Q235A steel with a corrosion rate of about zero inCuPT. The corrosions of Q235A steel in free of copper triazole preservatives or in carbendazimhydrochloride solution or in their were all serious and that of red copper were also serious incarbendazim hydrochloride solution or the mixed solution.5) When used in the condition of on the ground outdoor, the rational retention should beabout1.0kg/m3of mixtures of Copper/triazoles or0.2kg/m3of PPZ/TEB (mass ratio1:1) orbetween0.05~0.08kg/m3of CY, Hex and Tri.