Effects of Different Kinds of Coating Materials on Properties of Flat Pressed WPC Panels

The effects of different kinds of coating materials on the properties of flat pressed wood plastic composite (WPC) panels were studied in this work. Rotary-cut birch veneer, sliced oak veneer, phenolic impregnated paper, polyethylene (PE) film, and recycled polyethylene (rPE) layer were used as coating materials. One or two-side coating of WPC panels was carried out simultaneously with their flat pressing. No coupling agents were used for production of WPC. It was found that properties of flat pressed WPC panels improved by coating with all investigated coating materials. The highest values of modulus of rupture (MOR) were observed in WPC panels coated with rotary-cut birch veneer and MOR values were higher in along direction than in across direction of veneer fibers. The highest values of water resistance were observed in WPC coated with PE film or rPE layer. Coating of WPC with natural veneer leads to the decreasing of water resistance. Besides, water resistance of WPC coated with one side of natural veneer was higher in comparison with two side coated WPC panels with natural veneer. The two-side coating of WPC with phenolic impregnated paper, PE film or rPE layer leads to the decreasing of water absorption and thickness swelling.