Enhancement of dimensional stability and mechanical properties of HDF by adding waste paper are impregnated with melamine and urea resins

Wood based productions which are increasing in our country such as MDF, HDF, Chipboard, Plywood and OSB panel leave a high amount of valuable waste. The main theme of this work is the recycle of these wastes in the board and the positive effect on the production quality. Impregnated paper used as surface coating was investigated effect on the physical and mechanical properties of board to evaluate the wastes emerged during the impregnation process or later. In the study, changes in mechanical values were determined by using 5-10-15% impregnated waste decor paper and 5-15% overlay paper in produced high density fiberboard (HDF). The control sample at the tensile strength value was the lowest with 1,17 N/mm² and the highest at 1,44 N/mm² with 15% overlay waste paper. Compared with the control sample for bending strength, it was observed that the 15% decor and the overlay-added board increased by 7% and 8%, respectively. Looking at the 2-hour results for swelling, a minimum thickness increase of 5,34% was obtained with the addition of 15% decor paper. On the other hand, when the 24-hour swelling was checked, the sample 15% overlay was the lowest with value 12,36%. Formaldehyde emission was measured at the lowest control board with 8,70 mg/100 gr and ıt was meausered the highest with the addition of 15% overlay with 13,40 mg/100 gr. As a result of experiments has given good results on test sheets with impregnated overlay papers produced with 100% melamine formaldehyde resin. In addition to increased mechanical and physical properties, the increase in formaldehyde emissions and paper pieces left on the surface are not suitable for some surface treatments are disadvantages.