The glue pressing process of wood board is divided into hot pressing method and cold pressing method, and wood boards made by different glue pressing processes also have certain differences, so what is the difference between hot pressing method and cold pressing method of wood board ?
The combination of woodworking slabs is generally five layers, the glue is applied on the second and fourth layers, and the three-layer structure is glued on the core board.
Hot pressing of wood board:
The advantages are high production efficiency and good product gluing quality. The hot pressing method is mainly used in the manufacture of wood panels at home and abroad.
For example, in the manufacture of urea-formaldehyde resin bakelite board, the unit pressure is 0.6-1.2 MPa, the hot-pressing temperature is 100-120 degrees Celsius, and the hot-pressing time depends on the thickness and structure of the slab. For the cladding material part of the veneer in the slab, the hot pressing time is calculated as 50-60 seconds per 1 mm plate thickness. For the core plate, it needs to be hot pressed for 1 minute per 6 mm plate thickness. Generally, the thickness of the plate is 19 mm. About 7-11 minutes.
When producing phenolic resin bakelite board, higher hot pressing temperature and higher unit pressure are used than urea-formaldehyde resin glue. 11 minutes. The amount of formaldehyde released by using different glues is different, that is to say, the environmental protection performance. Shiyoumei board uses a new type of environmentally friendly vegetable glue, and its environmental protection level leads the industry and reaches E0 level.
The lower the hot pressing temperature, the smaller the internal stress of the slab, the higher the flatness of the sheet, the lower the pressure, the smaller the slab compression rate, the smaller the sheet deformation after hot pressing, and the smaller the warpage and unevenness of the sheet surface. The moisture content of the wood must go through the drying process to reach the standard. Generally, the moisture content of the wick is 8%–12%, the air drying in the north can be 6%–12%, and the air humidity in the southern region is high, but it should not exceed 15%. The moisture content of Shiyoumei board is controlled below 8% to avoid the formation of core foam (commonly known as foam board), and fully meet the standard.
Cold pressing method of wood board:
The advantage is that the internal stress of the finished product is small, the deformation is small, and the compression loss of the wood is small, and the disadvantage is that the production cycle is long.
When cold-pressed and glued, the plasticity of wood and the fluidity of the adhesive are poor, and a slightly higher unit pressure is required. When using urea-formaldehyde resin for cold-pressing, the unit pressure is 1.2 MPa, and the bonding time is 6-8 hours. The slabs are cold-pressed in stacks, and a backing plate needs to be placed at certain heights, so that the slabs are evenly stressed and the slab surface is flat.
The hot pressing method and cold pressing method of wood board are introduced here. From the above, the wood board made by the hot pressing method is better than the cold pressing method. winlong wood glue manufacturer will continue to answer your questions, welcome to contact us
