PROCESS FOR THE ACETYLATION OF WOOD AND ACETYLATED WOOD

摘要

The invention relates to a process for acetylation of wood having a density of above 400 kg/m3, particularly, of Southern Yellow Pine, and acetylated wood obtainable by this method. The described acetylation process allows the production of acetylated wood having higher acetylation levels, such as an acetyl content of at least 20% by weight. The acetylated wood has also a low residual acetic acid content, in particular, lower than 1% by weight. The invention is particularly useful for acetylation on industrial scale of pieces of solid wood, preferably, of wood beams.

主权项

1. A process for the acetylation of wood comprising the steps:
(a) in a reaction pressure vessel submerging wood having a moisture content of less than 5% by weight in an acetylation fluid comprising acetic anhydride and/or acetic acid at a temperature of 10° C. to 120° C., (b) increasing the pressure in the vessel to 2 to 20 bar for a period of 1 to 300 minutes, (c) removing excess acetylation fluid from the vessel, (d) introducing into the vessel an inert fluid, circulating and heating the fluid until the internal temperature of the wood begins to show an exotherm, controlling the supply of heat to the wood until the exotherm is complete and maintaining the internal temperature of the wood below 180° C., (e) heating the circulating fluid to a temperature of 85° C. to 160° C. for a time of 10 to 120 minutes to initiate a second exothermic reaction, controlling the supply of heat to the wood until the exotherm is complete and maintaining the internal temperature of the wood below 180° C., (f) removing the circulating fluid by evaporation under vacuum.