Eliminazione della formaldeide analizzabile in pelli con pelo conciate con composti di fosfonio

There are increasingly stringent limits on the amounts of analysable formaldehyde permitted in wool-on skins, particularly those that are used for clothing leather or for infant bedding. Some effective white tanning agents, notably those based on tetrakishydroxymethyl phosphonium (THPX) compounds produce some formaldehyde as a by-product of the tanning reaction. The objective of this work was to identify compounds that can be applied post tanning to remove most residual formaldehyde from the final product tanned with phosphonium compounds. Oxidising, reducing and conjugating agents were evaluated for their effects on analysable formaldehyde in solution and on woolskins tanned with THPX. Combination of the most effective of these formaldehyde scavenging agents were then further evaluated for their efficiency and effects on wool quality. The results showed that treatment of woolskins at the end of wet processing could be used to lower the residual levels of analysable formaldehyde to within tolerance limits with some detrimentale effects on the wool. Holding THPX-tanned woolskins in a wet condition lowered the residual formaldehyde concentrations.