Tosylamide/formaldehyde resin

Tosylamide/formaldehyde resin is a polymeric resin used as a plasticizer and secondary film-forming agent in nail polishes. While it was still in use as of 2023 its use has been diminishing in favor of hypoallergenic alternatives, due to the prevalence of reactions causing allergic contact dermatitis of the eyelids, face, and neck.

Production

TSFR is produced by condensing with formaldehyde. It consists of a mixture of short oligomers with repeating unit, terminated by or groups.

Nail polishes containing TSFR were first introduced in 1939, becoming a major cause of allergic contact dermatitis of the eyelids, face, and neck. Allergic responses are caused by the water-soluble contaminants 5-tosyl-1,3,5-dioxazinane and 3,5-ditosyl-1,3,5-oxadiazinane, rather than formaldehyde, which is only present in trace quantities.
Since the early 2010s, the prevalence of allergic reactions to TSFR has decreased, due to the widespread use of hypoallergenic alternatives such as tosylamide/epoxy resin, cellulose acetate butyrate, and polyester resins.