铜粉表面处理提升铜导电胶性能的研究

Study of Surface Treatment of Copper Fillers for Improvement of Electrically Conductive Adhesives

铜作为填料存在易氧化、氧化后电性能下降等缺点,限制了铜在导电胶中的应用.本文针对铜粉易氧化的问题,用乳酸和3-二乙基氨基-1,2-丙二醇(DEAPD)分别及同时对铜粉进行了表面处理.热失重分析显示,铜粉经表面处理后吸附了0.4%~0.7%的有机物,且因铜粉氧化而质量增加的拐点温度大幅提升,表明铜粉的抗氧化能力得到了增强.红外光谱分析表明微米铜粉表面吸附物分别为乳酸铜和胺.由于乳酸铜和DEAPD的保护作用,以及DEAPD对乳酸铜还原分解的促进作用,经表面处理铜粉填充的导电胶电性能大幅提升,体电阻率由(2.0±0.4)×10-2Ω·cm降低至(3.1±0.2)×10-4Ω·cm.初步的老化试验表明,经过表面处理的铜粉制备的导电胶具有更好的体电阻率稳定性.

Easy oxidation of copper has been the major obstacle for its application in electrically conductive adhesives（ECAs）.In this paper,the electrical performance of copper-filled ECA was improved by a simple surface treatment of copper fillers.The copper particles were treated with an ethanol solution of lactic acid and/or 3-diethylamino-1,2-propanediol（DEAPD）.Thermal gravimetric analysis（TGA）showed that 0.4% ~0.7%volatilizable substances remained on the surface of copper fillers after treatment.FTIR revealed the adsorbed substances were copper lactate and/or DEAPD.Due to the antioxidation effect of the copper lactate and/or aminediol,the weight gain temperatures related to the oxidation of copper in TGA measurement were obviously elevated.And the resistivity of the copper filled ECA was greatly reduced after surface treatment（from（2.0±0.4）×10-2Ω·cm to（3.1±0.2）×10-4Ω·cm）.Besides,the ECAs filled with surface-treated copper particles showed more stable electrical performance in a preliminary high temperature storage test.