脲醛树脂潜伏固化剂性能研究

Study on the properties of latent curing agents for urea-formaldehyde resins

通过示差扫描量热分析,固化时间和p H值测定研究了分别添加2种潜伏固化剂(六亚甲基四胺+过硫酸铵+对甲基苯磺酸+二乙醇胺,过硫酸铵+磷酸氢二铵)和常规固化剂氯化铵的脲醛树脂不同温度下的固化行为。结果表明,两种潜伏型固化剂的固化起始温度、峰顶温度均高于氯化铵,低温潜伏性能较好。低于固化起始温度时,添加两种潜伏固化剂的脲醛树脂体系p H值呈现中性偏碱,超过固化起始温度后,随着固化温度提高,脲醛树脂体系的p H值下降速度先慢后快,固化时间缩短。可以通过调控温度、p H值和时间三者关系实现对脲醛树脂预固化行为的控制。

The curing behaviors at different temperatures of urea-formaldehyde(UF)resins adding latent curing agents hexamethylene tetramine,ammonium persulfate,p-toluenesulfonic acid and diethanolamine,ammonium persulfate and diammonium phosphate and conventional curing agent ammonium chloride were investigated by differential scanning calorimetry and determination of curing time and p H value. The results showed that the onset temperatures and peak temperature of the UF resin with two latent curing agents were higher than those of ammonium chloride and the latency performance at lower temperature were good. Below the onset temperature,the p H values of UF resins adding two latent curing agents were neutral to slightly alkaline. The p H value decreased rate of UF resin systems was first slow and then fast and the cure time was shortened exceeding the onset temperature. The pre-curing behavior of UF resin could be controlled by regulating the relationship of temperature,p H value and the curing time.