WOODY BOARD AND MANUFACTURE THEREOF

PROBLEM TO BE SOLVED: To upgrade the resistance to water absorption and humidity and the strength and dimensional stability by binding an ozone-oxidized woody element obtained by ozoneoxidizing an acetylated woody element with a binder resin. SOLUTION: The acetylating treatment of a wood fiber is performed not only in the gas phase but also in the liquid phase. In the gas phase, the wood fiber is placed on a net and an acetylating agent such as acetic anhydride is heated to generate the vapor of the agent and thereby bring the vapor into contact with the wood fiber. The acetylated wood fiber is charged into a reaction tank to bring an oxygen gas entrained by an ozone generated by an ozone generator into contact with the wood fiber and obtain the ozone-oxidized wood fiber. Further, a binder resin such as a modified melamine is applied to the ozone-oxidized wood fiber by a spray process and the wood fiber is molded into a mat by a foaming process and then is molded in the form of a plate by heating it under pressure. After that, these plates are laminated to obtain a wood fiber laminated board. Thus the wood fiber laminated board shows the high resistance to water absorption and moisture and superb dimensional stability and outstanding strength.