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Density profiles are important structural features of wood-based panels, plywood also affect the physical and mechanical properties (such as product bending strength, internal bond strength and elastic modulus) is one important factor, plates of different cross-sectional density distribution may reflect the production process is reasonable or not. Cross-section through the regulation of product density distribution can be achieved on the mechanical properties of wood-based panels reasonable arrangements to meet the expected performance requirements. Sectional density fiberboard research will help producers control products fiberboard mechanical properties, control product quality, reduce production costs, and promote China fiberboard industries to power forward, but also will promote China's ecological construction and sustainable development. So the research profile density curve has a very important social and practical significance. This research study through single factor experiment Fiberboard hot pressing process parameters on the cross-sectional density fiberboard effects, including target thickness, target density, sintering temperature, mat moisture content, pressure closing speed. Through research, obtained dry density fiberboard sections of law: (1) the ideal profile density curve has the following features: pre-cured thin, high-density layer gradient large, uniform density core and core transition zone table curve smoothing. Actual production of the platen, the back surface of the slab heated first started in the back makes the heat transfer surface density profiles are asymmetric distribution curve \Curve consists of four parts: pre-cured layer, the surface area of ??high density, low density areas and tables core core transition zone. (2) the greater the target thickness, the highest surface density, the core density lower section undulation more apparent density, shape steeper. (3) increasing the target density, the highest surface density and core lowest density were increased, the surface density of the growth rate is less than the growth rate of core density; target density profile density curve only affects the overall position, and will not affect its shape. (4) With the pressing temperature, the surface of the water evaporation rate of the fiber, some cured adhesive polycondensation speed, the greater the thickness of the pre-cured layer, the highest surface density, the surface density increases with increasing temperature hot large, low-density core or small. 160 ℃ and 180 ℃ sintering temperature generated sectional density curve steeper, 140 ℃ of the curve is relatively flat. (5) help to increase the water content increased plasticity and thermal conductivity of the fiber, cellulose and hemicellulose to accelerate the hydrolysis reaction, to promote lignin and lower the melting point of the resin. Changes in moisture and density profiles pre-cured thickness has a significant effect. The higher moisture content, pre-cured layer is thinner, and the resulting density of the curve becomes flat section. (6) closing speed of the cross-sectional density distribution has a great influence. Pressurized closing speed, density difference between the core layer large table, section density curve steep, help to improve the board stiffness and bending strength; contrary table core density difference is small, cross-sectional density curve to flatten, helping improve the internal bond strength and edge nail holding power.
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