Hot forming method for high-strength complex material particle board

Abstract

The invention discloses a hot forming method for a high-strength complex material particle board. The method comprises the following steps of: placing a stainless steel plate and a complex material particle board assembly into a lower die frame sequentially; laying a steel mesh on the upper plane of the complex material particle board assembly, wherein the complex material particle board assembly comprises a shaving blank layer, and an upper complex material layer and a lower complex material layer which are arranged on the upper surface and the lower surface of the shaving blank layer respectively, and the shaving blank layer is formed by crushing plant particles, blending the crushed plant particles with adhesives and laying the mixture; and performing hot pressing on the complex material particle board assembly in the lower die frame by using an upper die, and unloading and cooling the die to obtain the complex material particle board. Effective steam diffusion channels can be formed in a hot pressing process, and steam in the shaving blank layer can be discharged in time, so that the increase of pressure is avoided after the steam aggregates, the probability of board explosion after the pressure is eliminated is greatly reduced, the strength uniformity of the complex material particle board is ensured and the strength of the complex material particle board prepared by the production process of the invention is improved.

Description

technical field [0001] The invention relates to a method for manufacturing a high-strength composite particleboard, in particular to a hot-press forming method for a high-strength composite particleboard, which belongs to the field of wood-based panel industry technology and low-carbon economy substituting wood for wood. Background technique [0002] With the continuous development of our country's national economy and the continuous expansion of international trade, China has become the processing center of the world. A large number of products need to be packaged and shipped. Every year, my country needs hundreds of thousands of cubic meters of wood for packaging. However, my country is a timber-poor country and needs to import a large amount of timber every year. Replacing wood with wood, protecting forests, utilizing waste materials, and low-carbon economy are always advocated by the state. Over the years, the state has issued a series of policies to encourage the deve...

AI Technical Summary

Problems solved by technology

It can be seen that during the pressing process, with the transfer of heat from the upper and lower molds of the hot press, the water contained in the wood waste will gradually turn into water vapor, the volume of the water vapor will gradually expand, and the pressure of the water vapor will also increase. Therefore, under the action of the upper and lower molds and high pressure of the hot press, the water vapor inside the shaving layer cannot be discharged because there is no effective exhaust channel, and it is far away from the external environment, while the corners of the shaving layer A small amount of water vapor will be discharged through the side. Therefore, the strength of the side part of the composite particle board made by hot pressing is often greater than that of the middle part, that is, the strength of the composite particle board is uneven. For the wood-based panel industry, the current technology is difficult to overcome.

In addition, with the continuous increase of the temperature of the hot press, more and more water vapor will accumulate, and the pressure of the water vapor will increase. At the moment of unloading the plate, due to the cancellation of the pressure of the hot press, the volume of the water vapor will suddenly increase. Expansion, its explosive force pulls the middle glued layer, resulting in the phenomenon of fried board

Severe frying phenomenon will cause the composite particleboard to be divided into two layers, and the second one will cause bubbling and partial delamination in the middle of the composite particleboard, and the most common frying phenomenon will cause the middle glued layer of the composite particleboard The combination of looseness and various fried board phenomena leads to a low qualified rate of finished composite particleboard

[0008] In addition, the commonly used composite particleboard production process, specifically, has the following deficiencies: First, the surface material of the commonly used composite particleboard is impregnated decoration material, which is airtight, and it is easy to cause the phenomenon of fried boards during the production process. At the same time, the impregnated decoration The tensile strength of the panel made of the material is not high

[0010] Therefore, in order to prevent the phenomenon of frying or reduce the probability of the phenomenon of frying, at present, it is generally achieved in the following ways: 1. Improve the dryness of raw materials, that is, reduce the moisture content of wood waste and reduce the water content in the hot pressing process. The amount of steam generated can avoid the formation of high-pressure water vapor. However, the cost of drying raw materials is high and uneconomical; reduce, that is, it is possible to avoid the formation of high-pressure water vapor, but this method virtually increases the cost of pressing composite particleboard

3. Add steel mesh directly on the upper and lower surfaces of the shaving layer, the purpose is to provide exhaust channels, but production practice has found that the effect is good when the pressure of hot pressing is small, but the effect is not obvious when the pressure is too high. After analysis, the reason The reason is that the steel mesh is in direct contact with the shavings layer, and under greater pressure, the stencil is easy to sink into the shavings layer, and the mesh of the steel mesh is blocked by the shavings; at the same time, during the physical and chemical process, the high-energy state substances always have the ability to diffuse to the low-energy state area. If the steel mesh is laid on the upper and lower surfaces of the particle layer, the temperature gradient cannot be formed on the upper and lower surfaces of the particle layer. After the moisture contained in the waste wood is gasified into water vapor, the water vapor inside the particle layer cannot diffuse. Good orientation, that is, this hot pressing method cannot form a good and effective exhaust channel during the high-temperature and high-pressure pressing process. Therefore, the possibility of obtaining high-strength composite particleboard is not high, and it cannot meet the requirements of replacing log products. ; 4. Low-temperature molding or normal temperature molding, the purpose is that during the pressing process, no pressurized gas can be generated inside the board. Although the phenomenon of fried boards is effectively reduced, the production efficiency is too low. At the same time, the strength of the composite particle board not high

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