Study On Formaldehyde Release Rule And Loading Rate Of Veneered Particleboard

In recent years,with the increasing shortage of wood resources in China,wood-based panels have become the main wood household materials in China.In order to increase the added value of wood-based panels,decorative processing of the surface of wood-based panels is an important way,thus decorative wood-based panels have become the mainstream products in wood-based panels.However,in the production and processing of wood-based panels,trialdehyde adhesives are commonly added as adhesives.In the use process,formaldehyde in trialdehyde adhesives will slowly release into the air and cause pollution.With the change of life style,people spend more and more time in indoor space,and pay more attention to indoor environmental pollution.As an important factor affecting indoor formaldehyde concentration,formaldehyde emission and loading rate of wood-based panels are naturally attracting more and more attention.Therefore,this paper takes veneered particleboard as the research object,uses(9-11)L desiccator to simulate formaldehyde release rule under closed environment.According to the mass balance of formaldehyde release process,,the theoretical formula for calculating the loading rate was deduced and verified.Then,the relationship between formaldehyde emission from veneered particleboard with different thickness and different formaldehyde emission amount and release time was investigated by using a 1 m~3 climate chamber.The stable formaldehyde emission of veneered particleboard under different air replacement rates was compared.According to the mass balance relationship of formaldehyde release process in climatic chamber,the formulas for calculating theoretical loading rate of particleboard are deduced and verified.Finally,by modifying the influence of temperature and humidity,the stable formaldehyde emission and theoretical loading rate of particleboard in actual environment are obtained.The accuracy of the calculation model is verified by 1 m~3climate chamber and real indoor space.The main results are as follows:(1)In closed space,the formaldehyde emission from three kinds of veneered particleboard to the air increased gradually in 1-7 days,and the formaldehyde concentration in the air basically reached a stable maximum after the 8th day.The stable formaldehyde emission value of veneer particleboard is negatively correlated with the loading rate of veneer particleboard.However,when the loading rate of veneer particleboard increases to a certain extent,the effect of increasing the loading rate on formaldehyde emission is limited.According to the mass balance of formaldehyde release process,the theoretical formula loading rate is deduced.The formaldehyde concentration approached the limit of 0.10 mg/m~3 stipulated by GB 50325-2010(2013 edition)after 8 days.This shows that the theoretical loading rate calculated is basically in line with the actual situation.(2)The formaldehyde concentration of the six kinds of veneered particleboard reached a high concentration at first,then gradually decreased and stabilized.With the increase of air exchange rate,the formaldehyde emission of six kinds of veneered particleboard decreased gradually.Moreover,the higher the formaldehyde emission,the greater the influence of air exchange rate on formaldehyde concentration in the air of the climate chamber.The formaldehyde concentration in the air of different veneered particleboards after 12 hours approached the limit of 0.10 mg/m~3 stipulated by GB 50325-2010(2013 edition)under different air exchange rates.This shows that the theoretical loading rate calculated is basically in line with the actual situation.(3)In the five validated rooms,the percentage of the difference between theoretical and actual loading rate is less than 5%in room one 1h and 12h,and in room two 12h?The percentage of the difference between theoretical and actual loading rate is less than 20%in room two 1h,room four 12h,and in room five 1h and12h.In most cases,the calculated loading rate of the theoretical formula is in good agreement with that of the actual space.