REDUCING TANNIN STAINING IN WOOD PLASTIC COMPOSITE MATERIALS

摘要

A process for reducing or eliminating tannins in wood flour so to reduce the level of tannins in wood/plastic composites made with the wood flour, and improve the finish provided by these products when in use. The process involves taking a precursor comprised of wood flour, dry wood waste or green wood waste, all of which contain high levels of tannin, rinsing the precursor with a solvent such as acetone, water or a base solution including Sodium Hydroxide (NaOH) or other salts, and heating the resultant mixture to a predetermined elevated temperature. The tannins in the mixture are rinsed out of the mixture with the solution out, with the remaining material which containing only a very slight amount of tannins. The remaining material is next dried, and then separated from the drying air stream through a cyclone or filter receiver. The material is then stored in bulk for delivery to a manufacturer of wood/plastic composites, an animal fur processor, or processed further into a finer wood flour.