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The drying process of wood flour for the material of biodegradable bags

Because wood flour contains a lot of water, soBefore molding, the wood flour needs to be sufficiently dried to remove moisture and volatile components. If the drying is not enough, smoke and dust will occur during the whole molding process, the product will contain air bubbles, and the color of the product will be dark and dull, which will also harm the physical properties of the product. Due to the different types and origins of wood flour, its organic chemical composition is also different, but its main components are generallyIt is cellulose, lignin and lignocellulose, and there are also extracts such as epoxy resin, other organic matter and water.The wood fiber contains many hygroscopic methyl groups, which are easy to absorb moisture, and the maximum water content can reach 14%~15%.When such a high amount of water is processed with epoxy resin, except for a part of the water that is volatilized by heating, most of it still remains in the composite system, causing loose smoke, polyurethane foaming, burning, and even Explosions and other situations in the barrel prevent molding, or have obvious adverse effects on molding and product characteristics. In order to ensure smooth molding processing and product quality, wood powder must be dried before use to reduce the water content of wood powder to4%The following is down to1%.generallyWhen the wood powder is dried and heated, the water volatilizes first, and then the easily soluble part of the lignocellulose undergoes a decomposition reaction. After further heating, the methylcellulose oxidizes and decomposes, and the lignocellulose dissolves.The dryness of wood flour, in which the temperature standard is important. If the dry temperature is higher than200°C,even higher than260°C,Then the compounding reaction is fast, it is difficult to stop the compounding reaction, and even there is a risk of fire;O2Under existence, wood flour is in200There will be strong smoke scattered up and down ℃, and the net weight will decrease5%~10%,Darkened and darkened; wood flour inO2medium heating, usually at260~290℃ will catch fire. In order to ensure safety, the heating is done in the exhaust gas without cheerfulness. If the temperature is less than160°C,The drying and volatilization of wood flour are slow, and the drying time should be increased.

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