Synthesis of melamine resins and their application to produce leather with high hydrothermal stability

摘要

A new, purely synthetic tannage has been developed which can produce leather having comparable hydrothermal stability with that of Chrome leather. It is based on oligomers or prepolymers of resins. More particularly, it relies on a specific particle size of resin and teh preferred resin is melamine- formaldehyde polymer, crosslinked preferably but not exclusively by hydroxymethyl phosphonium salt. This reaction is driven by heat, the high temperature also deaggregates the resin into smaller particles. In this way, the optimum temperature is determined by the degree of deaggregation, because the average particle size measured for any resin is inversely dependent on temeprature. The optimum particle size is 70-80 nm. These leathers dry soft and are white and lightfast. This new chemistry may be the basis for tanning in the 21st century.