Determination of Formaldehyde Conten in Leather: EN ISO 17226 Standard. Influence of the Agitation Method Used in the Initial Phase of Formaldehyde Extraction

Abstract

Given the carcinogenic character of formaldehyde, it should bereliably determined in any substrate. The EN ISO 17226Standard is the Official Method to quantify formaldehyde inleather. However, some misunderstandings may arise from thepractical conditions given by the Standard for the extraction offormaldehyde. Two agitation methods (magnetic agitation andreciprocal linear agitation), which fulfill the conditions of theStandard, have been used for the extraction of formaldehyde intwenty two samples of wet-blue split leather treated with resinssynthesized with formaldehyde and with/without the additionof vegetable compounds. The agitation method influences theformaldehyde content and differences between the agitationmethods depend on the formaldehyde resins and vegetablecompounds applied. Magnetic agitation leads to formaldehydecontents that are 26% greater than those obtained when thereciprocal linear agitation method is used. Major brandsspecify allowable limits for formaldehyde content, whichdepend on the user (adult or babies) and whether the article isin direct contact with the skin. A high percentage ofdisagreement (33.3%) has been observed between the agitationmethods in fulfilling the allowable limits. One-third of theformaldehyde content results that fulfilled the allowable limitswith the reciprocal linear agitation method failed when themagnetic method was applied. The situation urges theclarification of the shaking method in the EN ISO 17226Standard to avoid the high level of contradictory resultsbetween methods that meet the agitation conditions of theStandard.