Effect of the surface treatment in polyurethane and natural leather for the footwear industry

This aim of this paper is to analyse the peel strength of an adhesive joint with various types of surface treatments in order to contribute to the research and development of adhesives for the footwear industry. In the shoe industry, the adhesive properties are very important to ensure the quality of manufacture of the shoe. To better understand the behaviour of the adhesive joint, it is important to measure the peel resistance of the adhesive and use it to adjust the manufacturing process. For this work, joints were manufactured using natural leather, polyurethane (PU) and a solvent based polyurethane non structural adhesive. The influences of the application of physical surface treatments and/or primer on substrates in the peel strength of a T joint were analyzed. Several tests were used to characterize the surfaces of the substrates, including Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM) and contact angle measurements. It was found that certain surface treatments are required to obtain an adhesive joint capable of satisfying the minimum requirements of the shoes manufacturing sector.