Solvent-based polychloroprene contact adhesives: effect of tackifier

Solvent-based polychloroprene (CR) adhesive was formulated using four different types of tackifiers. Wood rosin (WD), coumarone-indene resin (CI), terpene-phenolic resin (TP) and para-tert-butyl phenol-formaldehyde (TBPF) resin were incorporated with CR at various amounts say 20-50 phr (parts per hundred rubber). The effect of nature and amount of resins on adhesion strength was measured on both leather to leather and rubber to rubber joints. Results indicated that the nature of resins greatly influenced the performance of the CR adhesive. The peel strength of CR/TBPF adhesive was higher than that of CR/TP, CR/CI and CR/WD adhesives. It was found that incorporation of TBPF resin also improved the thermal ageing resistance of the bonded joints. The properties of CR/resin adhesive were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The interaction between the resin and CR was studied using FTIR spectroscopy. All the four tackifiers used were compatible with CR as confirmed by the DSC analysis.