【作者】 朱黎明；

【导师】 邹献武；

【作者基本信息】 中国林业科学研究院 ， 木材科学与技术， 2021， 硕士

【摘要】 人造板作为室内装饰装修的主要材料,其安全环保性能一直受到人们的关注。由含醛树脂制造的人造板在使用过程中会向室内空气缓慢释放甲醛,因此人造板的甲醛释放量是其质量控制的关键指标之一,也是影响室内空气质量的重要因素之一。目前,人造板甲醛含量/释放量的检测方法主要有1m3气候箱法、穿孔萃取法和干燥器法。1m3气候箱法是强制性国家标准GB 18580-2017规定的人造板甲醛释放量的唯一法定裁决方法。但是,该方法存在检测周期长,检测费用高等问题,难以满足人造板企业日常生产控制的需要。因此,有必要建立1m3气候箱法与穿孔萃取法/干燥器法的相关性关系。同时,室内空气甲醛浓度也受到板材承载率和室内环境因素,如室内温度、相对湿度和空气换气率的影响。为使得装修后的室内空气甲醛浓度合格,有必要研究使用地区极限温湿度下的板材承载限量。而在室内空气甲醛浓度测定时,我国现行的室内空气质量标准GB 50325-2020和GB/T 18883-2002门窗密闭时间要求不一致:GB 50325-2020规定密闭门窗1h,而GB/T 18883-2002规定密闭门窗12h后才能测定室内空气甲醛浓度,因此合适的密闭时间常常是建筑提供方和居民用户冲突的焦点。为解决上述问题,本研究首先从理论上推导了人造板甲醛气候箱法与穿孔萃取法/干燥器法检测结果之间的数学关系,然后以多种类型人造板为研究对象,采用1m3气候箱法研究板材的甲醛释放规律,得到板材甲醛释放过程的传质系数和气候箱法与穿孔萃取法/干燥器法检测结果的相关性方程参数,以此为基础,得到气候箱法甲醛限量值所对应的穿孔法检测值/干燥器法检测值范围。然后,利用Berge方程和Merye公式,考察温湿度和换气率对人造板甲醛释放量的影响。根据全国主要城市最高月平均温度、最热月平均湿度和换气率数据,得到人造板甲醛释放量在各个城市的校正系数。根据室内装修甲醛污染物单区质量平衡关系,推导出基于极限甲醛释放量的人造板室内承载限量计算公式,并进行验证。最后,在气候箱和居室环境中考察甲醛释放量随密闭时间的变化关系,以确定合适的门窗密闭时间。通过以上研究得到以下结论:(1)人造板甲醛气候箱法检测结果与穿孔萃取法检测结果之间存在线性计算方程C∞(t)=A·C0+B;气候箱法检测结果与干燥器法检测结果之间亦存在线性计算方程C∞(t)=C·CW+B。人造板的甲醛释放特性参数(包括对流传质系数和分配系数)变化较大,但是同一类型同一厚度的人造板甲醛释放特性参数相对偏差稍小。(2)要使板材气候箱法甲醛检测值低于0.124mg/m3,对于厚度为7-10mm的纤维板/刨花板,穿孔萃取法甲醛检测值<4.1mg/100g;对于厚度为18mm的纤维板/刨花板,穿孔萃取法甲醛检测值<4.8mg/100g;对于厚度为9mm的胶合板,干燥器法甲醛检测值<2.01mg/L;对于厚度为15-18mm的胶合板/细木工板,干燥器法甲醛检测值<2.49mg/L。这一结果是否适用于所有人造板仍需大量数据进行检验。(3)高温高湿和低的换气率将提高人造板甲醛释放量测定值。对于不同温度下人造板的甲醛释放量值可以通过公式α=e-R(1/(t+273.15)-1/(t0+273.15))来校正,对于不同湿度下人造板的甲醛释放量值可以通过公式β=1+A(H-H0)来校正,对于不同换气率下人造板的甲醛释放量值可以通过公式1/C∞=1/keCeq·N+Cq来校正。根据国家统计局公布的全国主要城市最高月平均温度、最热月平均湿度和温湿度校正方程,可以得到全国主要城市板材甲醛释放量的温湿度校正系数。当供暖地区门窗密闭时换气率取0.2次/h,而非供暖地区门窗密闭时换气率取0.5次/h,可以求得全国主要城市人造板甲醛释放量在极限温湿度和对应城市换气率下的校正系数。推导出的基于极限条件下的人造板甲醛室内承载限量计算公式,在气候箱和实际房间中进行了验证,证明了计算公式的准确性。(4)人造板甲醛在密闭空间中初期释放较快,8-12h后甲醛浓度趋于稳定,因此,按GB/T 18883要求测量前密闭12h 比按GB 50325要求测量前密闭1h更为合理。更多还原

【Abstract】 As the main material for interior decoration,wood-based panels have always attracted people’s attention for their safety and environmental performance.Wood-based panels made of aldehyde-containing resin will slowly release formaldehyde to indoor air during using time.Therefore,the amount of formaldehyde released by wood-based panels is one of the key indicators for its quality control,and it is also one of the important factors affecting indoor air quality.At present,the detection methods of formaldehyde content/release in wood-based panels mainly include 1m3 climate chamber method,perforated extraction method and desiccator method.The 1m3 climate chamber method is the only legal ruling method for the amount of formaldehyde released from wood-based panels specified in the mandatory national standard GB18580-2017.However,this method has problems such as long detection cycle and high detection cost,and it is difficult to meet the daily production control in wood-based panel enterprises.Therefore,it is necessary to establish the correlation between the 1m3 climate chamber method and the perforated extraction method/desiccator method.At the same time,the indoor air formaldehyde concentration is also affected by the board loading ratio and indoor environmental factors,such as indoor temperature,relative humidity and air exchange rate.In order to make the indoor air formaldehyde concentration qualified after decoration,it is necessary to study the loading ratio limit of the board in the use area under the extreme temperature and humidity.When determining the concentration of formaldehyde in indoor air,China’s current indoor air quality standards GB 50325-2020 and GB/T 18883-2002 are inconsistent with the time requirements for closing doors and windows:GB 50325-2020 requires to close doors and windows for 1 hour,while GB/T 18883-2002 requires that the indoor air formaldehyde concentration can be measured only after the doors and windows are closed for 12 hours.Closeing time is often the focus of conflict between building providers and residents.In order to solve the above-mentioned problems,this research first deduces the mathematical relationship between the climate chamber method and the perforated extraction method/desiccator method detection results theoretically,and then taked various types of wood-based panels as the research object and adopted the 1m3 climate chamber method to study the formaldehyde release of the board,meanwhile obtained the mass transfer coefficient of the board formaldehyde release process and the correlation equation parameters of the climate chamber method between the perforated extraction method/desiccator method.Based on the study,the formaldehyde limit value of the climate chamber method that corresponds to the perforation method detection value/desiccator method detection value range is obtained.Then,the Berge equation and Merye’s formula were used to investigat the influence of temperature,humidity and air exchange rate on the formaldehyde emission of wood-based panels.According to the data of the highest monthly average temperature,hottest monthly average humidity and air exchange rate in major cities of China,the correction coefficients of formaldehyde emissions from wood-based panels in each city were obtained.According to the single-zone mass balance relationship of indoor decoration formaldehyde pollutants,the calculation formula for the indoor loading ratio limit of wood-based panels based on the limit formaldehyde emission was deduced and verified.Finally,the relationship between the change of the formaldehyde concentration and the sealing time in the climate chamber and the room environment is investigated to determine the appropriate closeing time of the doors and windows.The following conclusions were obtained through the above research:(1)There is a linear calculation equation C∞(t)=A·C0+B between the test result of the climate chamber method and the test result of the perforated extraction method;There is also a linear calculation equation C∞(t)=C·CW+B between the test result of the climate chamber method and the test result of the desiccator method.The formaldehyde emission characteristic parameters of wood-based panels(including convective mass transfer coefficient and distribution coefficient)vary greatly,but the relative deviation of the formaldehyde release characteristic parameters of wood-based panels of the same type and thickness is slightly smaller.(2)To make the formaldehyde detection value of the climate chamber method lower than 0.124mg/m3 for the fiberboard/particle board with a thickness of 7-10mm,the perforated extraction method formaldehyde detection value should be less than 4.1mg/100g;for the fiberboard/particleboard with a thickness of 18mm,the formaldehyde detection value of perforated extraction method should be less than 4.8mg/100g;for the thickness of 9mm plywood,the formaldehyde detection value of the desiccator method should be less than 2.01mg/L;for plywood/blockboard with a thickness of 15-18mm,the formaldehyde detection value of the desiccator method should be less than 2.49mg/L.Whether this result is applicable to all wood-based panels still needs a lot of data to test.(3)High temperature,high humidity and low air exchange rate will increase the measured value of formaldehyde emission from wood-based panels.The formaldehyde emission value of wood-based panels at different temperatures can be corrected by the formula α=e-R(1/(t+273.15)-1/(t0+273.15)).The formaldehyde emission value of wood-based panels at different relative humidity can be corrected by the formula β=1+A(H-H0),and the formaldehyde emission value of the wood-based panel under different air exchange rates can be corrected by the formula 1/C∞=1/keCeq·N+Cq.According to the highest monthly average temperature,hottest monthly average humidity,and temperature and humidity correction equations published by the National Bureau of Statistics,the temperature and humidity correction coefficients for formaldehyde emissions in major cities can be obtained.When the doors and windows are closed the air exchange rate is 0.2 times/h in the heating area,and the air exchange rate is 0.5 times/h in the non-heating area are closed,the correction factor of the formaldehyde emission in major cities can be calculated under extreme temperature,humidity and air exchange rate.The derived calculation formula for the indoor loading ratio of formaldehyde based on extreme conditions was verified in the climate chamber and the actual room,and the accuracy of the calculation formula was proved.(4)The formaldehyde of wood-based panels is released quickly in the closed space at the initial time,and the formaldehyde concentration tends to be stable after 8h-12h.Therefore,it is more reasonable to close 12h before measuring according to GB/T 18883 than for 1h before measuring according to GB 50325.更多还原