The Production Process Of Particle board

The production method of particleboard is divided into flat pressing method for intermittent production and extrusion method and rolling method for continuous production according to its slab forming and hot pressing process equipment. In actual production, the flat pressing method is mainly used. Hot pressing is a key process in particleboard production. Its function is to solidify the rubber in the slab, and to consolidate the loose slab into a board with a specified thickness after pressing. The process requirements are:

① Appropriate moisture content. When the water content of the surface layer is 18-20%, it is beneficial to improve the bending strength, tensile strength and surface finish, and reduce 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 skin layer to maintain proper in-plane tensile strength.

②Appropriate hot pressing pressure. Pressure can affect the contact area between the shavings, the thickness deviation of the board and the degree of transfer of glue between the shavings. According to the different density requirements of the product, the hot pressing pressure is generally 1.2 to 1.4 MPa.

③ appropriate temperature. Excessive temperature will not only decompose the urea-formaldehyde resin, but also cause the slab to be partially cured in advance when the temperature is raised, resulting in waste products.

④ Appropriate pressurization time. If the time is too short, the resin in the middle layer 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 subjected to a period of humidity adjustment treatment to make the moisture content reach a balanced state, and then sawed and sanded to inspect the packaging. However, it cannot be stacked in a hot state after pressure relief, otherwise it will increase the brittleness of the sheet. Molding technology refers to a technology that forms a product in one operation. There are 3 mature crafts. The hot molding method can use less or no sizing material, and rely on the activation and flow of lignin in the closed hot mold to act as a glue, but it needs to be cooled and demolded, the heat consumption is large, and the productivity is low, which has been gradually eliminated. The box molding method is to pressurize with a special press, and pressurize it into a product at one time, which is used to manufacture packaging boxes. The hot pressing method mainly manufactures furniture accessories, interior decoration accessories and pallets and other products. The adhesive is mainly urea-formaldehyde resin, and the surface of the product is pasted with veneer or resin-impregnated paper for one-time molding. In addition, there is a flat molding method that uses a template to press on the surface of the particleboard that has been made, or a formed slab that has not been hot-pressed to make a relief pattern.