The production method of particleboard is divided into the flat pressing method of intermittent production and the extrusion method and roller pressing method of continuous production according to the different slab forming and hot pressing process equipment. In actual production, the flat pressing method is mainly used. Hot pressing is a key process in the production of particleboard, which is used to solidify the rubber in the slab and consolidate the loose slab into a plate of specified thickness after pressurization. The process requirements are: (1) appropriate moisture content. When the moisture content of the surface layer is 18~20%, it is conducive to the improvement of flexural strength, tensile strength and surface finish, and reduces the possibility of bubbling and delamination of the slab during pressure relief. The moisture content of the core layer should be appropriately lower than that of the surface layer to maintain the appropriate plane tensile strength. (2) Appropriate hot pressing pressure. Pressure can affect the contact area between the shavings, the thickness deviation of the board and the degree of rubber transfer between the shavings. According to the different density requirements of the product, the hot pressing pressure is generally 1.2~1.4 megapascals. (3) Appropriate temperature. Too high a temperature will not only decompose the urea-formaldehyde resin, but also cause the slab to be cured prematurely when the temperature rises, resulting in rejection. (4) Appropriate pressurization time. If the time is too short, the middle layer of resin cannot be fully cured, the elastic recovery of the finished product in the thickness direction increases, and the plane tensile strength decreases significantly. The hot-pressed particleboard should be humidified for a period of time to make its moisture content reach a balanced state, and then sawed and sanded, and the packaging should be inspected. However, it cannot be stacked in a hot state after pressure relief, otherwise it will increase the brittleness of the plate. Molding technology refers to the technology that forms a product in a single operation. There are 3 types of mature processes. The hot mold method can use less rubber or no rubber material, and rely on lignin to activate the flow in the closed hot mold and play the role of gelatinization, but it needs to be cooled and demolded, the heat consumption is large, the productivity is low, and it has been gradually eliminated. The box forming method is pressurized with a special press, and the product is made by pressing at one time, which is used to manufacture packaging boxes. The hot pressing molding method mainly manufactures furniture accessories, interior decoration accessories and supporting board and other products, the adhesive is mainly urea-formaldehyde resin, and the surface of the product is laminated with veneer or resin impregnated paper, and it is molded at one time. In addition, there is also a flat molding method in which the surface of the particleboard that has been made, or the molded slab that has not been hot-pressed, is pressurized with a template to make a relief pattern.
