Thermal debonding pressure-sensitive adhesive blended with liquid crystal polymers

Abstract

With the development of the electronic information industry, semiconductor components and electronic devices are becoming smaller and thinner, which are easy to be damaged during processing and transportation. Pressure-sensitive adhesives (PSA) can temporarily fix and protect these electronic components. As PSA with adjustable peel strength can be easily removed after processing without damaging the electronic components, the research on debonding caused by external stimuli for PSA is a topic of great industrial value. Here, the thermal debonding PSAs have been prepared by incorporating liquid crystal polymers (LCP) into the acrylate PSA matrix. Firstly, the linear LCP (LLCP) blended PSA can lead to some degree of improvement in thermal debonding properties but the serious phase separation between LLCP and PSA matrix results in much lower 180o peel strength at room temperature even than the neat PSA. Secondly, to solve the problem of compatibility, we proposed a new strategy for that semi-IPN LCP PSA system. Through this strategy, the photocurable liquid crystal monomer (LCM) could perform photocuring with PSA matrix and in-situ form semi-IPN. The decreased ratio of the second system with 20 wt% and 50 wt% LCM content could reach 94.3 % and 95.9 % respectively upon heating from 20 °C to 80 °C, both of which are much higher than that of the neat PSA system (85.4 %). What's more, the 180o peel strength of PSA with 20 wt% LCM at room temperature is also 46.7 % higher than that of the neat PSA. Obviously, such an in-situ formed semi-IPN LCP PSA strategy has promising commercial application potential.