New preservatives based on copper chelates and copper complexes grafted to functionalized silica gel

At present the main products against wood decay are copper salts with other "co-formulating" substances such as boron, azoles and organic compounds. The role of these compounds is to increase the protective effect and the fixation of the copper derivatives to the wood, aiming at reducing their dispersion in the environment. Some copper-based preservatives described in literature consist of copper complexes with amines, among them ethanolamine is largely used owing to its copper fixative properties. The present research arises from the demand to realize a wood preservative with a broad spectrum of action, a low environmental impact and a good fixation into the wood. Our proposal in order to satisfy this goal is a preservative with copper chelates, in particular aminoacid derivatives and copper amine complexes grafted to functionalized silica gel. On the basis of the preliminary screening test it is possible to affirm that copper chelates alone and associated to boric acid, show a good efficacy against fungal decay to wood. The development of the research is going through the following steps: 1. Agar plate screening tests of systems based on copper aminoacid chelates alone and in mixture with boric acid 2. Vacuum-pressure impregnation of copper aminoacid chelates into the wood 3. Production of systems based on silica sol-gel materials (starting from alkoxysilanes) functionalized with organic groups having copper linking function 4. Accelerated efficacy test against fungal decay 5. Studies on the diffusion into wood of copper chelate compounds The accelerated tests against fungal decay gave promising and encouraging results.