Associate Professor Shohei Saito of the Graduate School of Science, Kyoto University announced that he has succeeded in developing a liquid crystal adhesive material that can be used even at high temperatures and can be peeled off with light through joint research with Nagoya University.
As the conventional adhesive material for temporary fixing, a type of adhesive material that can be peeled off by heat (hot melt type adhesive material) is widely used, but there is a drawback that the adhesive strength is lost at high temperature.On the other hand, as a type of adhesive material that can be peeled off by light, the application of a material that melts when exposed to light has been expected, but it has been difficult to develop a material that has both a "light peeling function" and a "heat-resistant adhesive function".
The research group designed and synthesized a unique molecule that responds to ultraviolet light, and further developed it into a material with high self-cohesive power called columnar liquid crystal (liquid crystal with a structure in which molecules are stacked in columns) based on this molecule. , Developed a new functional material and named it "light melt type adhesive material".This material shows high adhesive strength even at a high temperature of 100 ° C, and when exposed to ultraviolet light, the adhesive strength decreases by 85% with liquefaction, and when exposed to ultraviolet light with a general LED light source, it can be peeled off in just a few seconds. Was done.Furthermore, it has a recycling property that regains adhesive strength by heat treatment at 160 ° C, and has a fluorescent function that can distinguish between the bonded state and the non-bonded state by the difference in fluorescent color.
This research is said to contribute to the advancement of "temporary fixing and bonding using photoliquefaction materials" technology, which has begun to attract attention in recent years.In particular, the presentation of molecular-theoretical design guidelines and new methods of using columnar liquid crystals, which are necessary for achieving both heat-resistant adhesion and rapid photopeeling, is considered to be a highly valuable academic and industrial achievement.In the future, it is expected to be applied as an adhesive material for temporary fixing in various manufacturing processes for processing transparent members such as smartphones at high temperatures.