Application of a new modified epoxy adhesive for bonding fluorine rubber to metal

Adhesion of fluorine rubber to metals is an important issue. The aim of this work was to develop a new kind of adhesive for bonding fluorine rubber to metals. A new modified epoxy adhesive containing a special tackifier resin obtained from polysulfones with a high heat deflection temperature (HDT) was prepared. Study on the curing behavior of the adhesive was carried out. Properties of the adhesive and the effects of several main factors were studied by gelation time test, differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy. The optimum amount of the tackifier resin was found to be 50 phr; the average tensile lap shear strength could be achieved to a level of 8-10 MPa. Infrared attenuated total reflection (IRATR) spectroscopy indicated that the tackifier resin accelerated the establishment of epoxy resin adhesion to steel, and also promoted bonding and vulcanization of fluorine rubber. Easy diffusion of cyanamide ( decomposition compound of dicyandiamide (DICY) in the curing process) into epoxy resin and fluorine rubber facilitated the dissolution and reaction of DICY, and also promoted formation of complex bond between fluorine rubber and adhesive, hence an enhanced adhesion of fluorine rubber to metal was achieved.