The technology behind the MDF toilet seat(2)

3. Dryness(MDF toilet seat)
The drying process of MDF production process is mainly composed of drying host, drying pipeline and cyclone separator, fiber conveying device, dry fiber silo, etc. The discharge pipe of the refiner sucks in the wet fiber of the drying pipe and fully contacts with the hot air. The fiber is suspended and transported by air flow in the air duct. The fiber runs in the air duct for 4 ~ 5 seconds to quickly evaporate the moisture of the fiber and reach the required moisture content (8% ~ 12%).

4. Molding(MDF toilet seat)
Pavement forming is a very important process in the production process of MDF. This process includes slab pavement, preloading, edge alignment, cross section and other main parts. The requirements for the pavement process are: uniform slab density, stability, consistent thickness, continuous and stable slab weight control per unit area, and certain compactness.

5. Hot pressing(MDF toilet seat)
The hot pressing process of medium and high density fiberboard in China is intermittent multi-layer hot pressing process. Various process factors have an important impact on the properties of MDF.

A: Hot pressing temperature. The selection of hot pressing temperature is mainly determined by the type and performance of the plate, the type of adhesive and the production efficiency of the press. The selected temperature mainly depends on the comprehensive factors of raw materials, tree species, fiber moisture content, adhesive performance, slab thickness, heating time, pressure and equipment conditions.

B: Hot pressing pressure. The hot pressing pressure changes during the hot pressing process. When pressurizing, the pressure increases gradually to meet the slab thickness requirements, that is, the pressure should be reduced. The curing of adhesive, the formation of various bonding forces between fibers and water evaporation are mainly completed in the low-pressure section, and the pressure in the low-pressure section is generally 0.6 ~ 1.3mpa.

C: Hot pressing time. The determination of hot pressing time is mainly related to the properties of adhesive, curing time, fiber quality, slab moisture content, thickness, hot pressing temperature and pressure. The hot pressing time is generally expressed by the time required for 1mm plate thickness.

D: Moisture content of slab. In the process of hot pressing, the role of moisture in the slab is to increase the plasticity and thermal conductivity of the fiber. Therefore, an appropriate moisture content can ensure the quality of the plate, which is generally controlled at about 10%. If it is too high, the density gradient of the surface and core layer will increase, and the bonding force between the core fibers will be poor. During pressure reduction and steam exhaust, the water vapor is difficult to be eliminated, resulting in bubbling and delamination in the plate. If it is too low, the plate surface will be soft, The thickness of the pre cured layer reduces the strength of the plate.