Solvent-free bonding of shoe-soling materials

A variety of solvent-free methods to pretreat shoe-soling materials have been examined. With poly(vinyl chloride) and polyurethane, it was possible to achieve good adhesion without chemically modifying these materials using a polyurethane adhesive. With thermoplastic rubber SBS and vulcanised rubber SBR, it was necessary to chemically modify their surfaces to achieve good adhesion. With these elastomers, a water-soluble organic chlorine donor and a new electrochemical method were found to be very effective. In all cases, following surface treatment a water-borne adhesive was used and it was concluded that the manufacture of shoes without the use of organic solvents is perfectly feasible. The chemical changes caused by the pretreatments were studied using X-ray photoelectron spectroscopy.