Because there is a lot of moisture in wood flour, it is necessary to carry out sufficient drying of wood flour before molding to remove moisture and volatile components. If dryness is not enough, smoke and dust will occur in the whole process of forming, the products will contain bubbles, the color of the products will be dark and dull, and the physical properties of the products will also be endangered. Wood flour has different organic chemical composition due to different types and origin, but its main components are generally methylcellulose, lignin and lignocellulose, as well as extracted substances such as epoxy resin, other organics and water. Wood fiber contains many water absorbent methyl groups, which are easy to absorb moisture, and the water content can reach 14% ~ 15%

When such high moisture is produced and processed with epoxy resin, except that some water is heated and volatilized, most of it still remains in the composite system, resulting in smoke dispersion, polyurethane foaming, burning, and even explosion in the barrel, which makes it impossible to form, or has an obvious adverse impact on the characteristics of forming and products. In order to ensure the smooth molding, production and processing and ensure the product quality, the wood flour must be dried before application to reduce the water content of the wood flour to less than 4%, or 1%. Generally, when the wood flour is heated in a dry state, the water volatilizes first, followed by the decomposition reaction in the easily soluble part of the lignocellulose, and the methylcellulose is oxidized and decomposed after further warming, Lignocellulose dissolves.

The dryness of wood flour, in which the temperature standard is important. If the dry temperature is higher than 200 ℃ or even 260 ℃, the chemical reaction is fast, it is difficult to stop the chemical reaction, and even there is a risk of fire; In the presence of O2, wood flour will strongly smoke at 200 ℃, the net weight will be reduced by 5% ~ 10%, and the color will become dark and black; Wood flour will catch fire when heated in O2 at 260 ~ 290 ℃. In order to ensure safety, it is heated and dry in the waste gas without sunshine. If the temperature is less than 160 ℃, the drying and devolatilization of wood flour are slow, and the drying time should be increased.