导热聚氨酯灌封胶的制备与性能研究

PREPARATION AND STUDY ON PROPERTIES OF THERMAL CONDUCTIVE POLYURETHANE POURING SEALANT

采用聚四氢呋喃二醇(PTMG)、二苯基甲烷二异氰酸酯(MDI)以及球形氧化铝以一步法制备了聚氨酯灌封胶。研究了偶联剂用量、氧化铝粒径及填充量等对聚氨酯灌封胶导热性能的影响。通过正交实验设计确定影响灌封胶导热性能的最关键因素为Al 2O 3填充量。聚氨酯灌封胶的导热性能在偶联剂的加入后得到有效改善。加入相同含量的Al 2O 3时,2μm Al 2O 3填充的灌封胶导热性能较好,同种粒径下,灌封胶导热系数随Al 2O 3的加入逐渐升高。灌封胶体积电阻率随Al 2O 3填充量的增加逐渐降低,但灌封胶的绝缘性能仍能满足电子设备封装要求。

In this paper,polyurethane pouring sealant was prepared by one-step method using polytetrahydrofuran glycol(PTMG),diphenylmethane diisocyanate(MDI)and spherical alumina.The effects of coupling agent dosage,alumina particle size and filling amount on the properties of polyurethane pouring sealant were studied.The filling amount of Al 2O 3 was determined to be the key factor affecting the thermal conductivity of the pouring sealant by orthogonal experimental design.The thermal conductivity of polyurethane pouring sealant was effectively improved by adding coupling agent.When the same content of Al 2O 3 is added,the thermal conductivity of the pouring sealant filled with 2μm Al 2O 3 is better.At the same particle size,the thermal conductivity of the pouring sealant increases gradually with the addition of Al 2O 3.The volume resistivity of the pouring sealant decreases with the increase of Al 2O 3 filling,but its insulation performance can still meet the requirements of electronic equipment encapsulation.