High-performance PSA with dual-network structure for enhanced cohesion

Pressure sensitive adhesive (PSA) has great application potential in electronic packaging, flat panel display bonding and other fields. However, the low cohesion strength of these PSAs leads to their inherent low mechanical strength, which seriously hinders their application. In this study, PSA with dual network (DN) structure was prepared. Long chain polyurethane diacrylate (HPA) not only provides covalent cross-linking for linear acrylic polymers, but also provides non-covalent cross-linking of chain entanglements and hydrogen bonds, giving PSA excellent cohesion strength. DN-PSA not only has excellent bonding properties, but also has higher shear strength, its values are 21.9 N/25 mm and 92.5 KPa, respectively, which are increased by 16.5 % and 72.7 % compared with the control group. Although the DN structure reduces the elongation at break of PSA, it greatly increases the tensile strength of PSA, reaching 0.19 MPa. In addition, the PSA also has better heat resistance and higher light transmittance (> 90 %), which indicates that it is suitable for applications requiring high adhesion, cohesion and optical clarity, such as the bonding of flat panel displays.