Patent ID: 8173224
Filing Date: 2012-05-08
Classification: B27K,C08H,Y10T

Abstract:
1. A process for impregnating wood or wood based material using acetic anhydride, the process comprising the steps of: a. preheating a working solution comprising acetic anhydride to a temperature above the atmospheric boiling point of the working solution in a range of 170 to 200° C. to form a working solution at a super hot temperature, wherein sufficient pressure is applied throughout the preheating step to ensure the working solution is maintained in a liquid phase; b. contacting a wood or wood based material with the working solution at said super hot temperature and at an elevated pressure such that the working solution is maintained in the liquid phase, to cause impregnation of the liquid phase solution into the wood or wood based material and to react the liquid phase working solution within the wood or wood based material wherein the reaction of the liquid phase working solution is a substantially complete acetylation reaction; c. separating the wood or wood based material and any remaining working solution, waste material and/or by-products following the substantially complete acetylation reaction, whilst maintaining the elevated pressure; and d. releasing pressure to separate pressure kickback, the pressure kickback being any remaining working solution, waste materials, and by-products.