Contact allergens in p-tert-butylphenol-formaldehyde resin

Abstract: p-tert-Butylphenol-formaldehyde resin (PTBP-F-R) is used as a binder in many adhesive formulations and it consists of a complex mixture of substances, most of which are unknown. The resin has been reported to cause allergic contact dermatitis since the 1950s. The aim of the study was to investigate allergens in p-tert-butylphenol-formaldehyde resin (PTBP-F-R) and to isolate and identify sensitizers that are important factors for the development of hypersensitivity to PTBP-F-R in man. Chemical separation methods were used to isolate fractions and pure substances from the resin. These were patch tested in patients hypersensitive to PTBP-F-R. The sensitizing capacities and cross-reaction patterns of 11 isolated substances were investigated using the Guinea pig maximization test. In the present investigation 7 new allergens in PTBP-F-R were established and 1 more was strongly indicated. The allergens were found among monomers, dimers and trimers. Patch testing of formaldehyde and 4-tert-butyl-phenol, the raw materials for production of PTBP-F-R, indicated that these substances are not frequent allergens among patients hypersensitive to PTBP-F-R. 5-tert-Butyl-2-hydroxy-3-hydroxymethyl-benzaldehyde was considered to be an important allergen among the monomers. The dimers 4-tert-butyl-2-(5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzyloxymethyl)-6-hydroxymethyl-phenol and 4-tert-butyl-2-(5-tert-butyl-2-hydroxy-benzyloxymethyl)-6-hydroxymethyl-phenol were considered main allergens in the resin. The investigated substances were quantitatively determined in 2 PTBP-F-Rs and shown to be present in concentrations varying between 0.01 and 1.7% w/w.