利用PCB碱性蚀刻废液制备纳米铜导电胶

Preparation of nano-copper conductive adhesive from spent PCB alkaline etching solution

以碱性蚀刻废液为原料,采用液相还原法制备了纳米铜粉,将制备的纳米铜粉作为导电填充料添加到环氧树脂中制备出纳米铜导电胶。研究了纳米二氧化硅、硅烷偶联剂KH570和纳米铜粉的添加量对导电胶剪切强度以及纳米铜粉添加量对导电胶体积电阻率的影响,探讨了环氧树脂与固化剂聚酰胺适宜的反应时间。实验结果表明,所制备的铜粉为球状,粒径在40～100nm之间;当环氧树脂与固化剂聚酰胺树脂650的质量比为4∶1,纳米二氧化硅、硅烷偶联剂和纳米铜粉的加入量分别占环氧树脂–聚酰胺树脂体系质量的1.5%、4.0%和70%时,在90°C下固化1.0h,可以制备出体积电阻率为3.05×10-3Ω·cm、剪切强度达8.04MPa的导电胶。

Cu nanoparticles were obtained from spent alkaline etching solution using liquid phase reduction method, and then added as conductive filler to epoxy resin to prepare a nano-copper conductive adhesive. The effect of the amounts of nano-SiO2, silane coupling agent KH570 and Cu nanoparticles on the shear strength of conductive adhesive and the effect of Cu nanoparticle dosage on bulk resistivity of the conductive adhesive were studied. The optimal reaction time of epoxy resin with polyamide curing agent was discussed. The prepared Cu particles are spherical with a size of 40-100 nm. The conductive adhesive with a bulk resistivity of 3.05 ×10-3Ω·cm and a shear strength 8.04 MPa can be obtained by curing the epoxy/polyamide resin system with a mass ratio of epoxy resin to polyamide resin 650 equal to 4：1 containing 1.5wt% nano-SiO2, 4.0wt% silane coupling, and 70wt% Cu nanoparticles （all of the mass fractions are relative to the total mass of the epoxy/ polyamide resin system） at 90 ℃ for 1.0 h.