Construction of strong non-covalent interactions for preparation of flame-retarded acrylic pressure-sensitive adhesives with improved shear and peel strengths

摘要

The development of acrylic pressure-sensitive adhesives (PSAs) with good flame retardancy is of great importance for the optoelectronic, automobile, and aircraft applications. However, a well-known problem is that conventional flame retardants, while imparting good flame retardant properties to acrylic PSAs, compromise the cohesion and result in the unsatisfactory shear and peel strengths. In this work, flame-retarded acrylic PSAs with improved shear and peel strengths were successfully prepared by constructing a tight non-covalent crosslinking network that effectively counteract the negative effect of flame retardants on cohesion. In addition, the combination of dimethyl methylphosphonate (DMMP) and SiO2 increases the flame retardant effectiveness and reduces the overall required loading of flame retardants. As an example, when the amount of acrylic acid (AA) was 35 wt, acrylic PSA containing 12.7 wt DMMP and 2.5 wt SiO2 particles showed well-balanced adhesive properties and flame retardancy, with a shear strength of 3600 min and a peel strength of 15.0 N/25 mm, as well as a UL-94 V-0 rating. Meanwhile, it exhibited a high transmittance of above 90. Furthermore, TG-FTIR results confirmed that the flame-retarded behaviors occurred in vapor phase.