For 24 years, we have been dedicated to making high-quality boards, starting with moisture content – ​​"Stable"!

What is moisture content?

Moisture content of boards: Boards and their products under normal conditions contain a certain amount of moisture. In my country, the moisture content of boards is defined as the percentage of the weight of the moisture contained in the board to the weight of the board after it is completely dried.

Moisture content can be calculated using the weight of fully dry boards as the basis. The calculated value is called absolute moisture content, or simply moisture content (W, %).

Calculation formula:

W = (Gs - Ggo) / Ggo × 100%

W - Absolute moisture content

Gs - Wet board weight

Ggo - Weight of Oven-Dry Board

Equilibrium Moisture Content: Under certain air conditions, after a sufficiently long period of time, the moisture content of a board will tend to reach an equilibrium value, known as the equilibrium moisture content (EMC) of that environment. When the moisture content of the board is higher than the equilibrium moisture content of the environment, the board will release moisture and shrink; conversely, it will absorb moisture and expand. Therefore, a lower moisture content is not necessarily better.

All wood-based panels contain moisture before processing. Although they undergo drying treatment before production, they still retain a certain amount of moisture. Wood is composed of wood fibers; if the wood is too dry, it will absorb moisture from the air, while if it is too dry, it will evaporate moisture. Therefore, controlling the moisture content of the panels during drying has a significant impact on the quality of the panels and their finished products, including issues such as deformation and mold growth.

Excessive moisture content can cause the boards to warp and mold.

If the moisture content of the boards is not controlled properly when they leave the kiln during the drying process, such as when the moisture content is too high, they are susceptible to fungal infection, mold growth, discoloration, and decay during storage and transportation, especially in high-temperature weather. They are also prone to insect infestation and worm damage. In addition, during storage, the continuous evaporation of moisture inside the boards causes shrinkage, leading to deformation and cracking, which seriously affects the quality of the product and the service life of the boards.

Too low moisture content: can cause the board to crack and bulge.

If the moisture content of the wood is too low, it will directly reduce the bonding strength and other physical and mechanical properties of the board. For example, overly dry wood becomes brittle, less tough, and has reduced nail-holding power, making it difficult to saw and plan. It is also prone to breakage and chipping during processing. In addition, if the moisture content of the wood is too low, it will absorb moisture from the surrounding environment during transportation and use, leading to deformation.

Uniform moisture content: Longer service life of the boards

Wood-based panels are made of fibrous lignified tissue, exhibiting characteristics of swelling with moisture, shrinking with dryness, and anisotropy. Changes in moisture content cause expansion and contraction, creating internal stress within the panel. When this internal stress exceeds the tensile strength of the wood, cracks and deformation occur. Therefore, to prevent cracking and deformation, a drying process is essential. Only by maintaining and stabilizing the moisture content within a certain equilibrium range can deformation and cracking be effectively prevented, thus extending the panel's lifespan.

Drying is a crucial measure for controlling the moisture content of wood to a reasonable level. Controlling the moisture content of the substrate at every stage of production ensures the quality of the boards. From substrate to finished product, each eco-board undergoes at least three drying processes and a curing period of more than seven days to maintain a moisture content between 8% and 10%. This ensures the substrate is fully dried and shrinks, preventing moisture absorption, expansion, cracking, and deformation. It also increases the board's hardness and plasticity, thus guaranteeing product stability and bonding strength, making it durable.