At present, the hot pressing process of high density fiberboard in China is intermittent multi-layer hot-pressing technology, and various technological factors have important influence on the performance of MDF.
A: hot-pressing temperature. The choice of hot-pressing temperature mainly depends on the type and performance of the board, the type of adhesives and the production efficiency of the press. The selection of temperature depends mainly on the raw material, tree species, fiber moisture content, adhesive properties, slab thickness, heating time, pressure and equipment conditions of the comprehensive factors.
B: Hot pressure. Hot-Pressing pressure in the process is changing, pressure increases gradually, to meet the requirements of slab thickness, that is, should reduce pressure, and adhesive curing, fiber between the formation of a variety of binding forces, water evaporation is mainly in the low-pressure section, the pressure of the general 0.6~1.3mpa.
C: Hot pressing time. The determination of the hot-pressing time is mainly related to the properties of the adhesive and the curing time, the fiber quality, the moisture content of the slab, the thickness, the temperature and pressure of the hot pressing. Hot-pressing time is generally used for 1mm thickness of the time indicated.
D: The moisture content of the slab. In the hot-pressing process, the role of water in the slab is to increase the plasticity and thermal conductivity of the fiber, therefore, the appropriate moisture content of the board to ensure the quality of the general control in about 10%, if too high will make the table, core density gradient increase, the core layer of fiber between the knot, Buck exhaust steam, water vapor is difficult to exclude, resulting in the plate bubble, layered, If too low will make the board surface soft, pre-curing layer thick, plate strength.
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