Investigation of the feasibility of using powder coating for leather finishing

The feasibility of using powder coating technology, a process involving dry solid particulates, has been investigated for leather finishing for the first time. Results showed that powders can be applied to leather successfully using conventional electrostatic spraying facilities, provided that the leather is properly wetted with water. Powders can also be successfully applied to leather using non-electrostatic application methods, after pre-treating the leather surface with a tack agent, such as a soft resin, that makes the leather surface tacky and therefore receptive to powders. Finishing trials on leather using currently available commercial powder coatings have shown that a surface coating with an appearance no different to a conventional pigmented finished leather can be achieved without loss of area or softness, provided that stoving conditions are controlled (160 degrees C for 10 minutes). Although the coating was incompletely cured, it still provided excellent wet and dry rub fastness, sufficient dry adhesion and adequate wet adhesion properties. However, the coating was not completely satisfactory due to the occurrence of surface cracking and poor flexing endurance. This was because the powder coating used had not been specifically formulated for leather finishing.