Patent application number | Description | Published |
20090258943 | Hybrid strategies for reducing leaching of metal biocides from biodegradable substrates - Hybrid strategies generally involve treating biodegradable substrates with preservative compositions having at least two phases in which the metal biocide is distributed among at least the two phases and via equilibrium reactions moves between the two phases. Both phases are caused to contact the substrate in a manner so that the phases are in contact with each other during at least a portion of the treatment. In illustrative embodiments, the first phase is a liquid phase comprising complexed metal biocide dissolved in a liquid carrier, while the second phase comprises particles comprising the metal biocide, often precipitated and/or colloidal particles. The strategies and related compositions, processes, and treatments are hybrid in the sense that the strategies include both heterogeneous (insoluble) and homogeneous metal biocide constituents. Unlike heterogeneous strategies, hybrid strategies are less sensitive to particle size constraints and may use biocide particles with a wider range of particle sizes. Unlike homogeneous strategies, hybrid strategies are less sensitive to pH and may use a wider range of complexing agents, including mildly alkaline amines such as triethanolamine. | 10-15-2009 |
20100016426 | Post-impregnation treatments to improve distribution of metal biocides in an impregnated substrate - The present invention relates to post-treatment compositions and methods useful for modifying the distribution of metal biocide(s) in biodegradable substrates such as wood, other cellulosic products, starch-based products, and the like that are vulnerable to decay due to insects, fungi, microbes, and the like. The compositions include complexing agents of moderate strength that are able to facilitate mobilization and redistribution of metal biocide(s) in substrates without undue leaching. The compositions can be used, for example, to redistribute the metal biocide(s) into depleted regions of a substrate by redistribution of metal biocide from other regions of the substrate. Post-treatment compositions that include additional metal biocide can also replenish these regions with the freshly supplied, additional biocide. Thus, the depleted regions can be restored by redistribution and/or replenishment mechanisms. Service life of substrates in the field benefits by these post-treatments as a consequence. | 01-21-2010 |
20110091575 | STRATEGIES FOR REDUCING LEACHING OF WATER-SOLUBLE METAL BIOCIDES FROM TREATED WOOD PRODUCTS - Strategies that dramatically reduce leaching of water-soluble metal-containing biocides from treated biodegradable products. Aqueous, preservative compositions of the present invention incorporate one or more water-soluble metal species having biocidal activity and one or more agents that increase the leaching resistance of these metal species when impregnated into biodegradable products. Using one or more of these agents allows usage rates of the biocide impregnants to be dramatically lowered at the time of impregnation of the products. Because less of the metal biocide leaches in the presence of these agent(s), less biocide has to be added in order to meet desired loading goals. Generally, an agent of the present invention that reduces leaching of metal biocides is water soluble, is substantially nonionic in aqueous media, has a molecular weight greater than about 100, and has a vapor pressure less than that of water at standard temperature. Preferred agents are those including at least 10 weight percent, more preferably at least 16 weight percent, and even more preferably at least 20 weight percent oxygen. Examples of these preferred agents include (poly)ethers and/or nonionic surfactants including one or more oxyalkylene units in the backbone and/or as substituents of the molecule. | 04-21-2011 |