胶接胶合板的.doc

Uron结构降低脲醛树脂游离甲醛含量及胶接胶合板 甲醛释放量的研究 高伟 （北京林业大学材料科学与技术学院） 摘要：论文制备了含Uron结构的脲醛树脂（Uron树脂），并将其与普通脲醛树脂在一定条件下混合，得到各种混合脲醛树脂。通过混合脲醛树脂固化速度测定、游离甲醛含量测定、胶合板制造及其甲醛释放量与胶合强度测定、13C核磁共振分析等实验，研究了Uron结构及其含量对降低脲醛树脂游离甲醛含量及胶接胶合板甲醛释放量等的作用与效果。结果表明：1）Uron结构对混合脲醛树脂游离甲醛含量及胶接胶合板的甲醛释放量都有明显的降低作用，前者最大可达76%，后者最大可达84%；2）Uron树脂的制备时间可以减少至8小时； 3）Uron树脂与脲醛树脂的比例为20:100时，混合脲醛树脂具有较好的综合理化性能。 13C核磁共振 Gao Wei. Studies on Uron structure reducing free formaldehyde content and emission level of UF resin and plywood College Of Material Science and Technology, Beijing Forestry University, 100083, P. R. China. Three types of uron resin which contains much more uron cycle structure were prepared, and several mixed urea-formaldehyde (UF) resins were obtained by mixing uron resins with normal UF resins in this paper. The effects of uron structure and its amount on reducing free formaldehyde content of UF resins and formaldehyde emission value of its bonded plywood were studied by testing the curing time, free formaldehyde content of the resin, manufacturing plywood, testing free formaldehyde emission level, and bonding strength of the plywood, and analyzing 13C-NMR spectrum of the resins. The results indicate that: 1) The Uron resins can distinctly reduce free formaldehyde content and emission level of UF resin and its bonded plywood, the former can be reduced to 76% and the latter to 84%; 2) The manufacturing time of uron resin can be shortened to 8 hours; 3) The mixed UF resins with 20% uron resin have a relatively perfect performance. Key word: Uron resin; urea-formaldehyde resin; free formaldehyde; 13C-NMR 脲醛树脂胶粘剂及其胶接产品游离甲醛问题依然是限制其使用的一个重要原因。对其低毒化改性研究有许多方法，如改进合成配方与合成工艺、优化人造板施胶工艺及热压工艺，甲醛吸附材料与人造板的复合等[1]，其中改进合成工艺的研究受到最多关注。孙振鸢发现在固化的树脂中引入Uron环等环状衍生物,能相对提高树脂的稳定性，降低因水解而释放出的游离甲醛含量[2]。Hofmann. K和顾继友等指出在低温强酸性条件下合成脲醛树脂胶粘剂时由于部分Uron的生成而使胶的游离甲醛含量降低[3、4] C.SOULARD研究了Uron稳定存在的条件、结构特征与其他相关性能，将其与低摩尔比的脲醛树脂混合胶接强度比同摩尔比的脲醛树脂高，但富含Uron的树脂胶接的刨花板甲醛释放量依然很高[5] Uron树脂的合成原料只有尿素和甲醛，将Uron树脂作为一种添加剂来降低脲醛树脂的游离甲醛含量及其胶接制品的游离甲醛释放量，几乎不增加成本，具有一定的实用价值；通过研