What are the methods of wood preservative treatment?

In daily life, we will find that wood is prone to rot due to friction and that insects will grow inside it. If this happens, the quality of the wood will be greatly reduced and it may even become unusable. Therefore, if wood is to be preserved for a long time, it must be treated with anti-corrosion. This is very important and can avoid a lot of economic losses. So what are the current methods for anti-corrosion treatment of wood?

First, wood antiseptic treatment method - immersion method

At normal temperature and pressure, immerse the wood in a trough or pool filled with preservative solution, and keep the wood below the liquid surface at all times. The soaking time depends on the tree species, wood specifications, moisture content and type of agent, and is based on achieving the specified agent retention and penetration. In order to improve the treatment effect, ultrasonic and heating devices can be set in the soaking liquid, and surfactants can be added to improve the permeability of the wood. Depending on the length of the immersion time, the immersion method can be divided into instant immersion (seconds to minutes), short-term immersion (minutes to hours) and long-term immersion (hours to 1 month). Suitable for veneer and remedial preservative treatments, as well as temporary timber.

Second, wood antiseptic treatment method - diffusion method

According to the principle of molecular diffusion, with the help of the moisture in the wood as a carrier for the diffusion of the agent, the agent diffuses from high concentration to low concentration and diffuses into the deep layers of the wood. Therefore, the diffusion method for preservative treatment of wood must meet the following conditions:

1. The moisture content of small wood is high enough, usually above 35% to 40%, and green wood is best;

2. Water-borne agents (diffusion type) have high solubility and slow solidification;

3. The ambient temperature and humidity are high. According to the operation process, the diffusion method can be divided into slurry diffusion method, immersion or spray diffusion method, bandage diffusion method, drilling diffusion method (or drip diffusion method) and double-agent diffusion method. The diffusion method requires less equipment investment and has a simple production process. Easy to apply and promote in rural areas. Similar to this method is the sap replacement method.

Third, wood antiseptic treatment method - hot and cold tank

The principle of thermal expansion and contraction is used to make the gas in the wood expand and contract, creating a pressure difference in order to overcome the penetration resistance of the liquid, that is, heating the wood in hot liquid. The air in the wood expands and some of the water evaporates. The pressure inside the wood is higher than the atmospheric pressure, and the air and water vapor overflow to the outside. At this time, the wood is quickly placed in a colder liquid, the wood is suddenly cooled, and the air inside the wood creates negative pressure due to contraction, and the cold liquid penetrates into the wood. According to the processing method and the configuration of the cold tank, it can be divided into double tank alternating method, single tank hot and cold liquid alternating method and single tank cooling method. Due to the lower processing efficiency (compared with the pressurized method), the energy consumption per unit product is high. Generally used for small batches of wood preservative treatment.