Study on One Part Blocked Polyurethane-Ag Conductive Adhesive

Abstract

通讯作者: [email protected][中文文摘]以封闭型聚氨酯为基体、三羟甲基丙烷(TMP)为固化剂,制备了单组份银粉导电胶,并研究其性能.该聚氨酯基体由2,4-甲苯二异氰酸酯(TDI)、TMP和少量聚乙二醇进行缩聚,并与己内酰胺反应而得.在基体中添加TMP固化剂、银粉和二氧化硅并充分搅拌后制得单组份导电胶.通过红外光谱、剪切强度和电阻率的测定对产物进行了表征,结果表明,70℃下TMP、TDI的加成反应需要时间为4~4.5 h,与己内酰胺的封闭反应时间为3~4 h;银粉的质量分数为75%时产物性能最好;加入少量二氧化硅能够提高导电胶的剪切强度,但电阻率会随之升高.[英文文摘]The preparation and properties of one-component Ag powder conductive adhesive which consisted of TMP-TDI adduct as matrix and TMP as hardener were studied.TMP-TDI adduct was synthesized by TMP,TDI and PEG.Then the prepolymer was blocked by caprolactam to get blocked polyurethane.Hardener,Ag powder and fumed silica were added to the polyurethane to prepare one-component conductive adhesive through agitating well.The products were characterized by FTIR,moreover,their shear strength and electrical resistivity were measured respectively. The results demonstrated that the addition reaction of TMP and TDI needed 4~4.5 h, while the blocked reaction needed 3~ 4 h. The optimum mass fraction of Ag powder was 75%. Employing fumed silica to the conductive adhesive reinforced the shear strength and elect rical resistivity