Development of a pressure-sensitive adhesive utilizing a highly sensitive cross-linking system with photoanionic curing

Abstract

Pressure-sensitive adhesives (PSAs) can rapidly adhere to any substrate under low pressure. In general, acrylic PSAs are designed to undergo a thermal curing reaction. In recent years, UV-curable PSAs have attracted increasing attention because of their rapid curing and solvent-free production. However, radical curing cannot be performed in room air, and the development of an anionic curable type is desirable. Therefore, we synthesized a novel copolymer with anionic curability using an acetoacetate–Michael addition reaction cross-linking system and applied it to PSA tape. The developed PSA tape showed good performance 2 h after coating and UV irradiation. It comprises a specific polymer that reacts with high sensitivity even when a 1 wt% photobase generator is added. In addition, it has an ideal peel strength of 1.3 N cm–1 and it demonstrated high heat resistance up to 220 °C in a shear adhesion failure temperature test. The proposed polymer is expected to provide new benefits for PSA tape, such as temporarily fixing semiconductor devices. Illustration of photoanionic cross-linking of PSA by UV irradiation using photoreactive copolymers containing AOI and AAEM monomer units. The developed PSA tape showed good performance 2 h after coating and UV irradiation. The proposed polymer is expected to provide new benefits for PSA tape, such as temporarily fixing semiconductor devices.