"Board! Are you expanding?" A brief discussion on the impact of the thickness expansion rate of board water absorption on home life

"Board! Are you bloated?"

The annual "return of the south wind" from March to April and the "plum rainy season" from June to July are both indiscriminate "weapons of mass destruction" for furniture. Homes become damp and furniture can even swell, warp, crack, and mold. If your furniture made of wood panels frequently exhibits these problems during this time, beware, as the material's expansion rate through water absorption and thickness is likely insufficient.

▲Humid weather is a "lethal weapon" for homes

Water absorption thickness expansion rate

01. Definition of water absorption thickness expansion rate

Definition: The water absorption thickness expansion rate is the ratio of the thickness difference before and after water absorption to the thickness before immersion after a certain period of immersion, measured by cutting a certain amount of sample and immersing it in water according to the method specified in the standard.

In the board industry, the water absorption thickness expansion rate is a very important performance indicator, reflecting the board's water resistance and dimensional stability. The higher the value, the worse the board's water resistance. In other words, the higher the water absorption thickness expansion rate, the more likely the board will expand significantly in humid environments, leading to deformation, cracking and other problems.

▲Board, not afraid of water

02. Causes and Improvements of Thickness Expansion Rate Due to Water Absorption

There are two main reasons why the board absorbs water and expands: first, the raw material of the board is trees, and wood has inherent hygroscopicity, so it will expand when it gets wet; second, during the hot pressing process, the internal material of the board is compressed and deformed, and will restore its shape under certain conditions, so when it gets wet, it will rebound due to stress release.

Therefore, to improve the thickness expansion rate of the board due to water absorption, we can start from the selection of raw materials, the quality and quantity of adhesives, the optimization of hot pressing process, and the improvement of moisture content.

How to make royal coconut board?

01. Select excellent wood raw materials

The boards are made using the 5A material selection method. The growth conditions of trees in the raw material production areas are surveyed from multiple dimensions, including forest coverage, relative humidity, climate rainfall, and health index. Hundreds of tests are conducted on the wood over a period of 2-3 years to select high-quality logs with excellent material properties, thereby reducing the water absorption, thickness expansion rate of the boards at the source.

▲5A grade material selection method for boards, selected high-quality logs

02. Use soybean glue with strong waterproofness

The board is made of soybean bio-glue with a solid content of more than 46%. It goes through 8 production processes to ensure the freshness of the glue. It also has strong bonding, waterproof and environmental protection properties, which can hinder the entry of moisture to a certain extent, making it less likely for the board to absorb water and expand.

▲Use high-quality soybean glue and apply it evenly with roller

03. Continuously optimize hot pressing machinery and processes

Upgraded hot-pressing equipment for panels, featuring special material welded joints, ensures uniform pressure on the panels. A precision digital pressure gauge precisely controls the hot-pressing temperature. A three-step hot-pressing process, operating at a constant temperature of 130°C, significantly reduces the thickness expansion of the panels due to water absorption.

▲ Plate upgrade hot pressing equipment

04. Strictly control the density and moisture content of the board

Generally speaking, for lumber within the specified acceptable range, the higher the density and moisture content, the lower the thickness expansion rate due to water absorption. We use high-density logs and apply a low-temperature drying process for up to 10 days to achieve a balanced moisture content within the acceptable range, thus strictly controlling the lumber's water absorption expansion rate.

To sum up, don’t be afraid of humid weather. If you use good quality boards, they won’t “expand” so easily!