中国胶粘剂

LED固晶胶的导电、导热以及耐热可靠性对于大功率LED的发光性能与长期可靠性至关重要。本文采用环氧树脂、稀释剂、固化剂、固化促进剂、偶联剂、导电助剂和银粉等制备了LED固晶胶，然后通过改变导电助剂、稀释剂的种类，制备了不同的样品（E0～E4、R1～R5）。考察了导电助剂种类对LED固晶胶黏度、体积电阻率及导热性能的影响，并探究了稀释剂种类对LED固晶胶的常温及高温芯片推力、芯片-镀银框架残胶率及耐湿热性能的影响。研究结果表明：（1）导电助剂的加入，能够显著降低固晶胶的黏度。当导电助剂为己二酸（二元羧酸），固晶胶体积电阻率显著降低，热导率明显提升；当导电助剂中同时包含羧基和羟基时，体积电阻率反而增加，热导率降低。（2）分子刚性强（R4）、交联密度高（R5）的稀释剂，高温推力和残胶率表现不佳；单官刚性较强的苯基稀释剂（R1），在常温/高温芯片推力及残胶率间取得优异的平衡性能；柔性较好的脂肪族二缩水甘油醚稀释剂（R2、R3），综合性能介于两者之间。（3）高温蒸煮湿热老化试验表明，稀释剂中疏水性较好的苯基基团有助于改善固晶胶的耐湿热性能。

The electrical conductivity,thermal conductivity,and heat resistance reliability of LED die attach adhesive are crucial for the luminescence performance and long-term reliability of high-power LED.LED die attach adhesive was prepared in this article by using epoxy resin,diluent,curing agent,curing accelerator,coupling agent,conductive additive,and silver powder.Then,different samples(E0-E4,R1-R5) were prepared by changing the types of conductive additive and diluent. The influence of conductive additive type on the viscosity,volume resistivity,and thermal conductivity of LED die attach adhesive was investigated,and the influence of diluent type on die shear force at the room temperature and high temperature,residual adhesive rate of chip-silver plating frame,and moisture and heat resistance of LED die attach adhesive were explored.The research results showed that,(1) The addition of conductive additive could significantly reduce the viscosity of die attach adhesive.When the conductive additive was adipic acid(dicarboxylic acid),the volume resistivity of die attach adhesive significantly decreased and the thermal conductivity significantly increased. When both carboxyl and hydroxyl groups were present in the conductive additive,the volume resistivity increased,while the thermal conductivity decreased.(2) For diluents with strong molecular rigidity(R4) and high crosslinking density(R5),they exhibited poor performance in high-temperature die shear force and residual adhesive rate.For phenyl diluent(R1) with strong rigidity,it achieved excellent balance performance between room temperature/high temperature die shear force and residual adhesive rate.For aliphatic diglycidyl ether diluents(R2,R3) with good flexibility,their comprehensive performance was between the two.(3) The high-temperature steaming and moisture and heat aging test showed that the hydrophobic phenyl group in the diluent helped improve the moisture and heat resistance of die attach adhesive.