| 摘要 |
<p>ABSTRACT - 601675 The disclosure relates to a composite wood product containing acetylated wood elements having one of the following properties: (a) an average value in thickness swelling not exceeding 5% after subjection to 25 wet-dry/freeze-thaw cycles as described in Table II according to DIN EN 12467/12, (b) retaining an average value of at least 90% of its modulus of elasticity after subjection to 25 wet-dry/freeze-thaw cycles as described in Table II according to DIN EN 12467/12, (c) retaining an average value of at least 90% of its bending strength after subjection to 25 wet-dry/freeze-dry cycles as described in Table II according to DIN EN 12467/12, or (d) retaining at least 70% of its modulus of rupture after soaking for 48 hours in water at ambient temperature, wherein said composite wood product is obtained by a process, comprising acetylation of wood elements, wherein the elements are (a) treated with acetic anhydride at a temperature of 30°C to 190°C at a pressure of atmospheric to a gauge pressure of 1.5 MPa for up to 80 minutes and thereafter (b) heated with an inert gas which may be mixed with acetic anhydride or a mixture of acetic anhydride and acetic acid to a temperature of 150°C to 190°C at a gauge pressure of 0.1 to 0.5 MPa for a period of 5 to 300 minutes.</p> |
