Influence of the Composition on the Exploitation Properties of Combined Medium Density Fibreboards Manufactured with Coniferous Wood Residues

One of the maindisadvantages of medium density fibreboards (MDF) incomparison with particleboards is the higher price of the panels, due to the energy-intensivedefibration process. Studies on the possibilitiesfor replacing some part of the wood fibre mass in the composition of MDF withconiferous sawmill residues (shavings) obtained from bandsaw, are presented inthis article.The experimental plan is designed using the McLean andAnderson method for studying the properties of multi component systems in thepresence of constraints on the components. Thecontent of coniferous wood shavings varies up to 40%. The panels aremanufactured with a density of 720 kg.m-3. The content of urea-formaldehyderesin varies from 8 to 14% in order to compensate the negative impact of the inclusion ofconiferous wood shavings in the composition of the manufactured MDF panels. The main exploitation properties of the panels are determined. Experimental and statistical models on the influence of the studiedfactors are obtained by applying stepwise regression and optimization isperformed to obtain the best exploitation properties of MDF panels. As aresult of the study it was determined that in order to achieve the values ofMDF properties, required by the respective standards, the maximum permissiblecontent of coniferous wood shavings should be up to 10.6%, in which case thecontent of urea-formaldehyde resin should be above 10%. If the content ofurea-formaldehyde resin is below 10%, themaximum permissible content of coniferous wood shavings should be up to 5%.