环保型铜粉导电胶的研制

【作者】 李志红；

【导师】 钟建华；

【作者基本信息】 江西理工大学 ， 材料学， 2010， 硕士

【摘要】 本实验分别以双酚A型环氧树脂和咪唑为基体胶和固化剂,甲醛为还原剂,邻苯二甲酸二丁酯为增塑剂,用铜粉(300目)作导电填料,添加适当的偶联剂和稀释剂,制备了各向同性铜粉导电胶。通过L9(34)正交优化实验,获得了制备铜粉导电胶的最佳质量比。实验研究得到了偶联剂的种类及用量、导电填料的质量分数、晾置时间、固化温度和固化时间等因素分别对其导电性能和力学性能影响的一般规律。通过红外光谱分析(FTIR)得出了环氧树脂与咪唑间的最佳固化质量分数比,借助X射线能谱仪(EDS)分析了铜粉预处理前后含氧量的差异,用扫描电镜(SEM)观察了铜粉包覆硅烷偶联剂后分散性的变化,采用X衍射(XRD)和热重分析(TG)验证了硅烷偶联剂能显著提高微米级铜粉的抗氧化性能,利用万能数字电表、拉伸机、烘箱和恒温恒湿水浴箱分别检测了铜粉导电胶的体积电阻率、剪切强度和抗老化性能。实验结果表明:(1)当m(环氧树脂):m(咪唑)=100:8,m(偶联剂):m(铜粉)=1%,m(还原剂):m(铜粉)= 6%,铜粉添加量为整个体系质量的65%,且添加钛酸酯偶联剂时,制备的各向同性铜粉导电胶试样的体积电阻率可达1.5×10-3/Ω·cm,剪切强度为5.52 MPa。经6个月自然老化后,其体积电阻率为3.3×10-3/Ω·cm,且在180℃的高温下具有较好的稳定性和抗氧化性能,但在50℃85%RH湿热条件下的抗老化性能逊色。(2)以上述成分和比例制备的导电胶体系的渗流阈值是65%,低于该值时,铜粉导电胶的导电性随着铜粉质量分数的增大而增大,但剪切强度却相反,随着铜粉质量分数的增大而降低。此外,各个成分及用量对其性能的影响也不一样。(3)实验表明,固化温度为120℃时间为3h时能获得性能较好的导电胶,且固化前适当的晾置对于提高导电性能和力学性能同样有益。(4)SEM检测结果表明,硅烷偶联剂对提高铜粉的分散性有一定作用,但效果不是很明显。(5)XRD和TG检测分析表明,用硅烷偶联剂对铜粉进行改性的方法的确能提高铜粉的高温抗氧化性能。更多还原

【Abstract】 For the copper-filled isotropic conductive adhesives formulation, we used bisphenol-A type epoxy resin, imidazole as curing agent for the system and incorporating formaldehyde as reducing agent, along with dibutyl phthalate and silane couple agent, and adding Cu powders of 45μm diameter as conductive fillers. Optimal properties of Cu-filled ICAs were achieved by the L9(34) orthogonal experiments. In addition, the factors and their effects on the properties of conductive and mechanics were studied through adding different kinds of silane couple agent, weight percents of Cu, curing time and curing temperature, respectively.The optimal ratio between epoxy rein and imidazole was achieved by FTIR. The contents of oxygen on the surface of Cu powders before treated and after were determined by X-ray spectrometer. And the surface of the samples before and after coating silane couple agent were observed by SEM. In addition, X-ray diffractometer and thermo gravimetric analysis were applied to analyze the anti-oxidant property of Cu before they were coated silane couple agent and after. The bulk resistivity, shearing strength and aging performence were characterized by digital multimeter, stretcher and oven,respectively. The experiment results can be summarized.(1)The Cu-filled ICAs with their bulk resisvivity and shearing strength were 1.5×10-3/Ω·cm and 5.52 Mpa respectively when the ratio between epoxy rein and imidazole was 100:8, the percent of titanate couple agent was 1% and formaldehyde was 6%, and adding Cu up to 65 wt.%. After aging for 6 months under natural conditions, the bulk resisvivity can remain at 3.3×10-3/Ω·cm. In addition, the samples had good conductive property even exposed at 180 degrees. However, their properties under 50℃85%RH were poor.(2)The percolation threshold of ICAs is 65 wt.%. The conductivity of the samples increases with the percents of Cu and shearing strength decreases on the contrary. And the main factors which effected on the properties of Cu-filled ICAs were different.(3)The experiment showed that the optimal cuing process was 120℃for 3 h.(4)The result of SEM showed that silane couple agent may has a protective effect against some reunion, however, the protection of silane couple agent is not effective.(5)The results of XRD and TG showed that the anti-oxidant property of Cu after coated silane couple agent was really better than the untreated due to the polymer of silane couple agent had high thermal stability even exposed under hing temprature.更多还原