Chemical changes in rubber allergens during vulcanization.
Allergic contact dermatitis to rubber is caused by residues of chemicals used in manufacturing a rubber product. Several different additives are used to achieve a final product of the desired characteristics. Accelerators such as thiurams, dithiocarbamates, and mercaptobenzothiazoles are often among the additives responsible for allergic reactions recognized by dermatologists. The chemistry of the vulcanization process is complicated; as it occurs at an elevated temperature with a mixture of reactive chemicals, the compositions of the initial and final products differ. This paper investigates the changes in composition of common allergens during vulcanization, doing so by chemically analysing various rubber formulations at different stages of the process. Major changes were found in which added chemicals were consumed and new ones produced. An important observation is that thiuram disulfides rarely appear in the final rubber although they may have been used as additives. Instead, thiurams are often converted to dithiocarbamates or to products formed by addition to mercaptobenzothiazole structures, if these have been used together with thiurams as accelerators.
Department of Dermatology, University Hospital, Lund University, SE-221 85 Lund, Sweden. ola.bergendorff@skame.se
Ola
O
Bergendorff
Christina
C
Persson
Anna
A
Lüdtke
Christer
C
Hansson
D000485:Allergens / Q000009:adverse effects / Q000032:analysis* / Q000737:chemistry; D052160:Benzothiazoles / Q000009:adverse effects / Q000032:analysis* / Q000138:chemical synthesis; D002851:Chromatography, High Pressure Liquid; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D006801:Humans; D012408:Rubber / Q000009:adverse effects / Q000032:analysis* / Q000138:chemical synthesis*; D013057:Spectrum Analysis; D013859:Thiocarbamates / Q000009:adverse effects / Q000032:analysis* / Q000138:chemical synthesis; D013893:Thiram / Q000009:adverse effects / Q000032:analysis* / Q000737:chemistry
D000485:Allergens; D052160:Benzothiazoles; C524859:N,N-dimethylthiocarbamylbenzothiazole sulfide; D013859:Thiocarbamates; D013893:Thiram; C028000:dibenzothiazyl disulfide; D012408:Rubber