【作者】 刘悦婷；

【导师】 梅长彤；

【作者基本信息】 南京林业大学 ， 环境工程， 2011， 硕士

【摘要】 人造板是目前室内装修中应用最为广泛的木质复合材料,生产中绝大多数用脲醛树脂作为胶粘剂。脲醛树脂人造板在生产和使用过程中会对生产车间和室内环境造成甲醛污染,严重威胁人类身体健康。因此,研究人造板的甲醛散发规律、散发机理对防治室内空气污染具有重要意义。本论文以脲醛树脂刨花板为研究对象,从生产原料、生产工艺入手,系统地研究了工艺参数对刨花板热压过程中甲醛散发量、成板甲醛后续散发规律以及板子物理力学性能的影响,分析了三者变化规律的反应机理和内在联系,主要成果如下：(1)设计了一套收集人造板热压过程中甲醛散发量的装置,密封性良好,可重复性好,可充分收集人造板热压过程中的甲醛散发总量。(2)板密度从500 kg/m3到800 kg/m3,热压过程中单位质量刨花板的甲醛散发量降低了32.4%,总体呈降低趋势,板密度对干燥器法甲醛散发影响不显著。(3)刨花含水率从2%到8%,热压过程中的甲醛散发量增加了175.3%,甲醛干燥器值增加了49.8%,都近似呈对数增长。(4)施胶量从6%到12%,热压过程中的甲醛散发量增加了81.7%,甲醛干燥器值增加了63.3%。都近似呈直线上升。(5)热压温度从160℃到180℃,热压过程中的甲醛散发量增加了32.5%,近似呈曲线上升趋势；甲醛干燥器值下降了41.3%,近似呈直线下降趋势。(6)热压时间从15 s/mm到30 s/mm,热压过程中的甲醛散发量增加了240.1%,近似呈指数趋势增加；甲醛干燥器值下降了48.2%,近似呈乘幂趋势降低。(7)人造板在热压过程中造成的甲醛污染非常严重,除了未施胶刨花板的甲醛MAC值小于国家规定的甲醛最高容许浓度(MAC) 0.5 mg/m3外,其他大部分都远远超标,所有板子MAC的均值为2.27 mg/m3,是国家规定限值的4.54倍。(8)随着工艺参数的改变,刨花板的物理力学性能与热压过程中的甲醛散发规律存在一定的相关性。(9)通过优化生产工艺参数,可使甲醛在热压时充分参与固化反应,从而得到物理力学性能较好同时兼顾热压过程甲醛散发量低、成板后甲醛散发也低的平衡点。更多还原

【Abstract】 Urea-formaldehyde adhesive (UF) was widely used in the wood-based panel boards produced, which were usually applied in the furniture products and interior decoration. The workplace and indoor air pollution produced when the UF-boards were in the processing, also in the productions using, which is very harmful to the human health. Therefore, the studies on formaldehyde emission rule and the releasing mechanism had great significances on the preventing of indoor air pollution. This dissertation was focused on formaldehyde emission about particleboard which was manufactured by UF resin. The formaldehyde emission would be different when the raw materials and production technology were changed. The effects of technological parameters on the formaldehyde emission during particleboard hot-pressing, the desiccator’s value, the main physical and mechanical properties were investigated. The changed rules of the three inner links and the reaction mechanism were also analyzed systemically. The main results were as follows:(1) A set of collecting device for formaldehyde emission during hot-pressing of wood-based panel was designed with good sealing performance and repeatability, which ensured that formaldehyde was fully collected during hot-pressing process. So far, it hadn’t been seeing in the reports of china.(2) The value of unit mass of the particleboard formaldehyde emission during hot-pressing was reduced when the particleboard’s density increasing, the formaldehyde emission value was reduced by 32.4% when the density increased from 500kg/m3 to 800kg/m3, however, the influence of density by the desiccator method was unobviously.(3) Along with the increasing of particleboard’s moisture content, both the value of formaldehyde emission during hot-pressing and the desiccator value had a logarithmic growth. When the moisture content of particles increased from 2% to 8%, the formaldehyde emission value during hot-pressing increased by 175.3%, and the desiccator value increased by 49.8%.(4) Both the formaldehyde emission value during hot-pressing and the desiccator value increased linearly with the content of adhesive increased. The formaldehyde emission value during hot-pressing increased 81.7% and the desiccator value increased by 63.3% when the content of adhesive increased from 6% to 12%.(5) With the hot-pressing temperature increasing, the formaldehyde emission value during hot-pressing presented a curve upward trend, but the desiccator value decreased linearly. The formaldehyde emission value during hot-pressing increased 32.5% and the desiccator value dropped 41.3% when the hot-pressing temperature increased from 160℃to 180℃. (6) With the extension of hot-pressing time, the value of formaldehyde emission during hot-pressing presents an exponential upward trend, but the desiccator value decreased in a power function trend. The formaldehyde emission value during hot-pressing increased by 240.1% and the desiccator value dropped by 48.2%(7) When the hot-pressing time increased from 15 s/mm to 30 s/mm. The formaldehyde pollution was serious during wood-based panel’s hot-pressing. In the experiments, all of the particleboard’s maximum allowable concentration (MAC) value during hot-pressing was much more than the occupational exposure limits (MAC:0.05mg/m3) except the particleboard without resin. The MAC mean value of all the boards was 2.27mg/m3, which was 4.54 times of the national occupational exposure limits.(8) Along with the changes of technological parameters, the main physical mechanical properties and the formaldehyde emission value during hot-pressing had certain correlations.(9) If the process parameters were optimized, the formaldehyde could be reacted much more in the curing during hot-pressing, so the better-quality boards with good physical mechanical properties and lower formaldehyde emission both during hot-pressing and after the production were probably produced.更多还原