Higher Adhesion Strength Over 10 N/mm Between Rubber and Fluoropolymer Film When Treated by Atmospheric Plasma-Graft Polymerization

An evaluation of the adhesion between rubber and fluoropolymer films treated by atmospheric plasma-graft polymerization is conducted to realize a low-permeation fuel rubber hose covered with fluoropolymer. The low-permeation fuel rubber hose is important for reducing vehicular evaporative emissions. Although fluoropolymers have extremely low permeability for fuel, it is difficult to bond them with other materials, such as rubber, because of their low adhesive properties. Plasma surface modification has been investigated to improve the adhesive properties of fluoropolymers. However, it is difficult to realize effective and permanent surface treatment using plasma alone. Based on the new and effective combined plasma surface-modification technique for fluoropolymer films, we previously proposed an atmospheric-pressure plasma method followed by graft polymerization of hydrophilic monomers such as acrylic acid (CH
₂
= CHCOOH). In this study, three types of rubber, isobutylene isoprene rubber (IIR), ethylene acrylic elastomer (AEM), as well as white-colored ethylene acrylic elastomer (white AEM), and two types of fluoropolymer films, denatured PFA-1 and denatured PFA-2, were prepared. The treated fluoropolymer film and rubber were adhered using vulcanized adhesion, and then the 180° peeling strength test was conducted. The results show that an average peeling strength of 12.6 N/mm and a maximum peeling strength of 15.3 N/mm, which are over 10 N/mm, are attained for the sample of vulcanized bonding of the treated denatured PFA-1 and AEM.