高端LED全彩显示屏用双组分缩合型有机硅灌封胶的研制

Preparation of two-part silicone potting for LED full color display

以α,ω-二羟基聚二甲基硅氧烷为基胶,配合沉淀白炭黑、电子级硅微粉、增塑剂、交联剂、偶联剂和自制增粘剂等,制得LED全彩显示屏用双组分缩合型有机硅灌封胶。研究了A、B组分质量比、增塑剂用量对灌封胶性能的影响;探讨了自制增粘剂用量对灌封胶粘接性能的影响;同时对灌封胶耐热老化性能进行了研究。结果表明,随着B∶A质量比增大,灌封胶的线性收缩率也变大;随着甲基硅油添加量增加,胶料混合后的黏度和硬度不断减小;当自制增粘剂添加量为5.7%时,灌封胶拉伸剪切强度最大,可达0.32 MPa;耐热老化性能研究表明,150℃热老化1 000 h后,硬度增幅为7度,粘接性能良好。

The two-part silicone potting material designed for potting on LED full color display, was prepared with α, ω-dihydroxy polydimethylsiloxane as the basic resin and other processing aids such as precipitated silica, electronic grade silica powder, plasticizer, cross-linker, silane coupling agent and self-made tackifier, etc. The influences of the component weight ratio of B/A and plasticizer amount on the properties of silicone potting were investigated. A tackifier was prepared with 2,4,6,8-Tetramethylcyclotetrasiloxane, allyl glycidyl ether and ethenyltrimethoxysilan. The influence of tackifier amount on bonding strength of silicone potting was discussed. The thermal aging of the potting was investigated. The results showed that the shrinkage of potting increased as the ratio of B/A increased; the viscosity and hardness of the potting decreased as the methyl silicone oil increased. When the addition amount of self-made tackifier was 5.7 phr, the tensile strength of potting could reach 0.32 MPa. The results of thermal aging test showed that after thermal aging for 1000 hours, the hardness increased 7 degrees of Shore A, and the potting still hold a good bonding performance.