低温快速固化环氧导电胶的制备与性能

采用E-51型环氧树脂为导电胶基体树脂, 低分子量聚酰胺树脂(PA)为固化剂, 填加经硅烷偶联剂(KH550)改性后的纳米级和微米级铜粉及助剂制备导电胶。首次采用了液态固化剂(低分子量的聚酰胺酯), 以解决导电胶制备过程中填料用量受限的难题。通过正交试验方法探讨了导电胶中导电填料的含量、导电填料配比、硅烷偶联剂用量和还原剂添加量对导电胶粘接性能和导电性能的影响, 对导电胶的制备工艺进行了优化, 获得了制备导电胶的最佳方案。测试结果表明该导电胶能够在60 ℃下4 h内快速固化。在填料质量分数为65%时, 导电胶具有最低的体积电阻率3.6×10-4 Ω·cm; 导电胶的抗剪切强度达到17.6 MPa。在温度为85 ℃、湿度(RH)为85%的环境下经过1000 h老化测试后导电胶电阻率的变化和剪切强度的变化均不超过10%。 

Preparation and performance of epoxy resin conductive adhesive with fast-curing feature at low temperature

A thermoset type isotropic conductive adhesive (ICA) was prepared by epoxy resin E-51 as the matrix, nanosized and microsized copper powder modified by silane coupling KH550 as the conductive fillers, polyamide resin with low molecular weight as the curing agent, and some other additives. A new liquid curing agent, polyamide resin with low molecular weight, was used which solved some difficult problems during the preparation of ICA, such as limit of quantity of conductive fillers. The effects of different factors such as curing agent, silane coupling agent, reducer, and conductive filler on the bonding performance and the conductivity for conductive adhesive were discussed by the orthogonal experiments. The preparation parameters of the conductive adhesive were optimized, and the optimal preparation parameters for the conductive adhesive was obtained. The results show that optimum conditions of conductive adhesive are composed of 65% of nano-and micro-copper powder with curing time for 4 hours at 60 ℃. The adhesion strength reaches 17.6 MPa and the bulk resistivity is 3.6×10-4 Ω·cm. The change rates of bulk resistivity are less than 10% at the high temperature (85 ℃) and the high humidity(RH 85%).