Preparation of a novel waterborne adhesive and its peel strength between leather and polypropylene substrates

Polypropylene (PP) is widely used in many industrial applications, including the preparation of interior parts for automotive vehicles. However, the poor adhesion between PP and PP or leather is problematic. In addition, adhesives that contain organic solvents could emit hazardous gases inside a vehicle if used for interior parts. Therefore, waterborne adhesives are required to bond leather to PP. While waterborne adhesives prepared with 2-hydroxyethylmethacrylate- grafted styrene-butadiene rubber (SBR- g -HEMA) have shown good peel strengths (3.0 kgf/2.5 cm 2 ), its long curing time (2 days at 80 °C) greatly reduces the production rate. In this study, we prepared a novel waterborne adhesive composed of SBR modified with PP-grafted maleic anhydride (PP- g -MAH). This adhesive exhibited a higher peel strength (3.6 kgf/2.5 cm 2 ) than that of pre-existing adhesives after curing for only 15 min at 80 °C. Furthermore, this adhesive exhibited a similar peel strength (2.78 kgf/2.5 cm 2 ) when cured for 15 min at 70 °C.