Abstract:

The di-imine matter synthesized from methyl isobutyl ketone(MIBK) and m-xylylenediamine (MXDA), abbreviated as MIBKDI, is a frequently-utilized latent curing agent for one-component epoxy adhesive. The remained MXDA in the curing agent, due to its direct cross-linking with epoxy resin, would significantly impair epoxy_{adhesive's stability in storage. In industrial synthesis processes, ultrahigh molar proportion between MIBK and MXDA (>10∶1) is applied to enhance MXDA conversion as much as possible; nevertheless, MIBK loss and energy consumption for its recovery would result in extensive cost. In this research, the orthogonal experiments were used at first to make weight analysis and factorial effect analysis for reaction temperature, time and reagent ratio; and the single-factor experiments were carried through systematically to investigate the effects of reaction time and reagent ratio on MXDA conversion ratio. It is resulted that the epoxy adhesives could be stable enough for sale with the curing agent synthesized with the MIBK/MXDA molar ratio higher than 5∶1, while the reaction was sustained for 4 h under 170℃. Under the typical condition for adhesion, the cured epoxy resin behaved excellent with shear strength up to 12.9 MPa and tensile strength equal to 19.2 MPa, which can meet the demand defined in National Standard GB/T 2567—2008. When the MIBK/MXDA molar ratio was optimized to be 5∶1 for curing agent synthesis, energy consumption is greatly reduced, while MIBK consumption is effectively saved, and the total cost is reduced considerably.}

Key words: methyl isobutyl ketone, m-xylylenediamine, latent curing agent, epoxy adhesive, storage stability, optimization

摘要：

间苯二甲胺（MXDA）与甲基异丁基酮（MIBK）合成的甲基异丁基酮二亚胺（MIBKDI），是单组分环氧胶常用的潜伏型固化剂。反应残余的MXDA，可直接与环氧树脂发生交联，显著降低储存稳定性。工业生产通过超高酮胺比使MXDA充分转化，但MIBK损失大、回收能耗高。本研究首先采用正交实验对反应温度、时间和酮胺比进行权重分析和因素效应分析，然后通过单因素实验系统研究反应时间、酮胺比对MXDA转化率的影响。结果表明，酮胺摩尔比超过5∶1（反应温度170℃、时间4 h）制备的固化剂，储存稳定性满足市场需求。在典型条件下，环氧树脂完全固化后剪切强度12.9 MPa，拉伸强度19.2 MPa，达到国家标准GB/T 2567—2008要求。与工业方案相比，酮胺比优化为5∶1以后，能耗大大降低，同时MIBK消耗有效节约，总成本得到客观降低。

关键词: 甲基异丁基酮, 间苯二甲胺, 潜伏型固化剂, 环氧树脂, 储存稳定性, 优化