Vacuum drying method
The vacuum drying method is a method in which wood is piled up in a closed container and dried at a lower pressure than atmospheric pressure to remove part of the resin, and vacuum drying is suitable for wood having good air permeability. Vacuum drying method, can not achieve the desired effect. Vacuum drying is mainly characterized by drying faster than other methods, compared with other drying methods, drying time can be shortened about 25 ~ 1 2. Japan's Naito Truth [4] Drying of Douglas fir wood by high-frequency vacuum drying is considered to be effective for degreasing and mainly in the early stages of drying, since the moisture removal in the wood is in the early stages of drying, so its degreasing action is also in the early stages of drying. ] And other larch wood for cooking, vacuum and artificial drying, that cooking, vacuum degreasing effect is good, because the cooking to increase the permeability of wood.If the cooking, vacuum drying after artificial drying degreasing effect is better, because the vacuum drying Shorten the drying time.But the vacuum drying equipment is complex, the investment is high, there are vacuum drying machine manufacturers can use this method.To generally improve the degreasing effect, often using two or more degreasing method combination, such as Liquid immersion plus steam drying, pharmacy impregnation vacuum, steam vacuum pressure vacuum and other methods. The manufacturer can be based on the actual situation of the factory, choose the appropriate method for their own.
High temperature drying method
High temperature drying is considered to be a more effective degreasing method. Cech [2] has done a degreasing test of Korean pine wood, using a high-temperature drying method to reduce the average rosin by 274% and turpentine by 40 1%. If high temperature drying The rosin can reduce the rosin by 30% and the turpentine can be reduced by 65%. This method is mainly to remove the turpentine of the resinous acid that dissolves the solid because the boiling point of the turpentine is about 1 50 to 2 3 0 ° C, If the coexistence with water can be reduced to below 100 ℃. [3]. Turpentine volatile at high temperatures, and under high temperature steaming conditions to reduce the boiling point of turpentine, while high temperature steam to improve the permeability of wood, can be effective To evaporate the turpentine component, the remaining solid rosin after treatment will not exudate. High temperature plus steam combined dry is the most effective practical method, it does not need to add any equipment only the original drying kiln, so less investment , But many people use it, but some people think that after the role of high temperature and humidity, dry wood after the pine wood surface dark gray, dim, lost the original natural wood color, processed into products after the tan.
Catalytic polymerization
Under certain conditions, α and β - pinene will produce polymerization, the formation of yellow sticky material, so that it is fixed or associated with wood, such as aluminum chloride, heme, bleach, tested proved to be effective But the most commonly used boron trifluoride, the boron trifluoride alcohol solution applied to the surface of the plate, it will change the composition of the resin in the terpene, α and β - pinene can be converted into less volatile or Non-volatile, sticky, non-flowable fractions. Brush the boron trifluoride solution at a concentration of 26% on the surface of the resin to reduce the effect of resin bleed [1]. But this method only Wood surface treatment, the wood within the terpene does not change, will still move to the surface of the resin and produce seepage, so this method is suitable for dry after the low moisture content of wood, in the wood before finishing.
