The influence of "moisture content" on the board

Different industries have their own professional terms. If you want to understand an industry, you can start with the professional terms. The editor will divide it into several special topics to lead everyone to understand the various professional terms in the board industry. Today we will decipher "moisture content" together.

▲Logs waiting to be processed

Ⅰ What is “moisture content”?

Under normal circumstances, boards or wood products contain a certain amount of moisture. In my country, the percentage of the weight of the wood containing moisture to the weight of the wood after drying is defined as the moisture content of the wood.

The calculation formula for moisture content is as follows:

W=(Gs-Ggo)/Ggo×100%

Where: W--absolute moisture content of wood

Gs - wet wood weight

Ggoo--absolute weight

Ⅱ What impact does “moisture content” have on board quality?

During daily use, our furniture may be found to be deformed, cracked, warped, bulging, etc. This is basically caused by the "moisture content" in the boards and their products being too high or too low. Only when the moisture content in the boards reaches a balanced state can the above situations be effectively avoided.

Ⅲ What impact does “moisture content” have on formaldehyde release?

Formaldehyde (HCHO) is a colorless, soluble, irritating gas. It has become the primary indoor air pollutant in my country. It can be absorbed through the respiratory tract, and its aqueous solution, formalin, can be absorbed through the digestive tract, negatively impacting human health. At 0.1 mg/m³ in indoor air, an unpleasant odor and discomfort are noticeable. 0.5 mg/m³ can irritate the eyes and cause tearing; 0.6 mg/m³ can cause throat discomfort or pain. Higher concentrations can cause nausea, vomiting, coughing, chest tightness, shortness of breath, and even emphysema. Reaching 30 mg/m³ in the air can cause immediate death. The moisture content of the board after sizing also affects formaldehyde emissions from wood-based panels. Under the same conditions, the higher the moisture content, the greater the formaldehyde release.

Ⅳ What should be the appropriate “moisture content”?

Ⅴ How is Conrail board made?

To sum up, the importance of moisture content to a good board is evident. In order to control the moisture content, what processes are used in the board?

⒈Natural drying + drying kiln drying

In order to achieve a relatively balanced and stable "moisture content" for the boards, a combination of natural airing and constant temperature kiln drying is adopted in the drying process;

▲Natural drying

▲Constant temperature drying kiln

2. Repeated health care to stabilize the water content

The logs will have a curing period before processing, so that the wood can adapt to the humidity of the local air and facilitate better processing later. During the processing process, they will also go through several curing links. After the finished products are produced in the factory, they are sent to warehouses in various places. The stores will also have a curing period to allow the boards to adapt to the local environment and achieve the purpose of balanced moisture content.

▲Slab health care

▲Storage and maintenance of finished board

Ⅵ Can the “moisture content” meet the standard through the above process?

▲National standard for moisture content of artificial boards

▲Actual measurement of the "moisture content" of the board