U.S. Borax, Inc.

Mark J Manning

Jeffrey Douglas Lloyd

Frederick M Ascherl

Jeffrey D Lloyd

David M Schubert

Marek Gnatowski

Christine Mah

Cecilia L Stevens

Preservative composition for lignocellulosic-based composites providing rapid and long-lasting protection against insect and fungal attack, in both low and high moisture environments, through the use of a combination of higher solubility and lower solubility borates. Pesticidal amounts of a lower solubility borate and a higher solubility borate are combined before or during their incorporation into a lignocellulosic-based composite. Useful low solubility borates include copper borate, zinc borate and barium metaborate. Useful high solubility borates include boric acid, boric oxide, ammonium borate and alkali metal borates such as sodium borate. Some alkaline earth metal borates, including calcium borates, calcium magnesium borates, magnesium borates and calcium sodium borates, are of intermediate solubility and may be used effectively as either a low soluble or high soluble borate depending on the combination used.

Mixed solubility borate preservative

The addition of zinc borate alone or together with a hindered amine light stabilizer and ultra-violet light absorber to organic materials such as thermoplastic polyolefin resin, as is common in wood-plastic composites, provides a substantial reduction in the ultra-violet light degradation of the resin in comparison with similar materials made without zinc borate. This could provide substantial improvements in the long term durability of wood-plastic composites and other organic materials which are used in exterior environments and subject to ultra-violet exposure from the sun.

Performance enhancement in the stabilization of organic materials

Preservative composition for lignocellulosic-based composites providing rapid and long-lasting protection against insect and fungal attack, in both low and high moisture environments, through the use of a combination of higher solubility and lower solubility borates. Pesticidal amounts of a lower solubility borate and a higher solubility borate are combined before or during their incorporation into a lignocellulosic-based composite. Useful low solubility borates includes copper borate, zinc borate and barium metaborate. Useful high solubility borates includes boric acid, boric oxide, ammonium borate and alkali metal borates such as sodium borate. Some alkaline earth metal borates, including calcium borates, are of intermediate solubility and may be used effectively as either a low soluble or high soluble borate depending on the combination used.

Lignocellulosic-based woodfiber-plastic composite products containing a pesticidal amount of calcium borate is resistant to attack by wood destroying fungi and insects. The preferred calcium borates are the calcium polytriborates having a CaO:BOmolar ratio of about 2:3 and calcium hexaborates, having a CaO:BOratio of 1:3. Composites can be produced by combining the calcium borate with particles of the lignocellulosic material and the thermoplastic resin binder, and heating and extruding the resultant mixture through a die to form the composite product.

Lignocellulosic composites

Lignocellulosic-based composite products containing a pesticidal amount of calcium borate is resistant to attack by wood destroying fungi and insects. The preferred calcium borates are the calcium polytriborates having a CaO:B O molar ratio of about 2:3 and calcium hexaborates, having a CaO:B O ratio of 1:3. Composites can be produced by combining the calcium borate with particles of the lignocellulosic material and an adhesive resin, and forming the composite, generally with heat and pressure.

Lignocellulosic composite

Lumber, plywood and other wood products are preserved from attack by fungi, termites and wood-destroying insects as well as fire and flame by treatment with a novel zirconium borate-containing preservative composition. The preservative can be formed by combination of a source of boron such as boric acid and the water-soluble salts thereof with a water-soluble zirconium salt. The ZrO.sub.2 :B.sub.2 O.sub.3 weight ratio in the preservative composition is in the range of from about 0.75:1 to about 10:1.

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Santa Monica, CA, United States of America

Mark J Manning