Dyestuffs and formaldehyde content in split leather treated with formaldehyde resins

摘要

Formaldehyde resins are present in textile, leather and wood industries. Due to the harmful character of formaldehyde, different alternatives have been found to exclude or reduce its content on processed goods. However, the effect of dyestuffs on the formaldehyde content of goods containing formaldehyde-synthesized resins has not been studied up to date. The aim of this work is to check if the presence of free amino groups in the structure of dyestuffs exerts an influence on the formaldehyde content on leathers treated with formaldehyde synthesized resins. Six dyes, belonging to three different families (acid dyes, direct dyes and basic dyes), have been taken as examples to evaluate how their structures affect the reaction with formaldehyde present in leather. The variation of the formaldehyde content in dyed leathers with respect to control samples (treated with resin only) and its evolution with time have been also considered.