改性脲醛树脂甲醛与尿素的摩尔比及其影响

分析了三聚氰胺改性脲醛树脂甲醛与尿素的终摩尔比对改性树脂的固体含量，固化时间，游离甲醛，胶合强度，预压强度，甲醛释放量的影响。结果表明，固含量随终摩尔比的增大而减小，固化时间随终摩尔的增大而显缩短；胶合强度随终摩尔的增大而增大；当终摩尔比在1．0－1．1变化时，预压强度随终摩尔比的增大而减小；当终摩尔比在1．1－1．4变化时，预压强度随终摩尔比的增大而增大；甲醛释放量与终摩尔比呈线性关系。终摩尔不是影响树脂中游离甲醛的最显的因素。

The Effects of Final-molar Ratio of UF Resin Modified by Melamine Agglutination

The effects of final molar ratio of UF resin modified by melamine on capability(solid content,gelation time,free formaldehyde content)of modified resin and plywood performance(glue bond strength,prepressing intension,formaldehyde emission)were studied.The variables included the final ratio of UF,the quantitative change of melamine,polyvinyl alcohol and the temperature of final.The experiment was designed by the mathematical model of "Quadratic orthogonal rotation combination design".According to the results of the experiment,while the final molar ratio of UF increased,the solid content followed decreased.The gelation time notably shortened while the final molar ratio of UF increased.Not only the final ratio of UF,but also the craftwork and the temperature influenced the free formaldehyde content.Glue bond strength increased too while the final ratio of UF increased.While the final molar ratio of UF increased between 1.0 and 1.1,the prepressing intension followed decreased;while the final molar ratio of UF increased between 1.1 and 1.40,the prepressing intension followed also increased.There does exist linear relationship between formaldehyde emission and the final ratio of UF.