The internationally accepted method for preserving wood is to use an insoluble water-based preservative to apply preservatives to the wood fibers while applying pressure to the wood in a closed vacuum tank. The pressure-treated wood is more stable, and the preservative pavilion can effectively prevent mold, termites and insects from invading the wood. This allows the treated wood to have excellent corrosion resistance for long-term use in harsh outdoor environments. Sodium Tripolyphosphate, Technical Grade, Sodium Phosphate Sanji Chemical Trade Co., Ltd. , http://www.lysjchemical.com