Synthesis of acrylic hot-melt adhesive based on poly(methyl methacrylate)-b-poly(2-ethylhexyl acrylate) copolymer using atom transfer radical polymerization for a nylon fabric bonding system

Adhesives, such as hot-melt adhesives (HMAs), are widely used in the textile industry for bonding layers of materials and have replaced traditional sewing methods. The block copolymer is a common type of HMA that provides excellent physical features and mechanical properties compared with others. Acrylate-based monomers, methyl methacrylate (MMA), and 2-ethylhexyl acrylate (2-EHA) were used as ingredients to form a linear block copolymer using atom transfer radical polymerization. MMA provides excellent cohesive strength, while 2-EHA provides good adhesion properties. An end-brominated poly(methyl methacrylate) (PMMA-Br) macroinitiator was synthesized from a MMA monomer and initiator, with the best composition obtained by the addition of a 0.6 mol initiator. The macroinitiator had the lowest molecular weight with highest conversion (97%). The addition of a 0.3 mol macroinitiator showed the lowest molecular weight with the highest conversion of acrylic copolymer PMMA- b-poly(2-ethylhexyl acrylate) (PEHA). The glass transition temperature increased with the addition of the macroinitiator concentration, from −43.7℃ to −37.6℃. The thermal stability was reduced with the addition of macroinitiator content, from 332.37℃ to 286.81℃. The shear strength and peel strength of the PMMA- b-PEHA HMAs on nylon fabrics were enhanced from 11.24 to 16.92 kg cm−2 and from 0.29 to 0.61 kg cm−1, respectively, and did not change significantly after being washed 50 times and then kept in low-temperature storage, with the addition of the macroinitiator concentration. The block copolymer PMMA- b-PEHA prepared in this study could be used as a HMA for nylon fabric bonding systems.