Demonstration of contact sensitizers in resins and products based on phenol‐formaldehyde

Abstract

12 phenol-formaldehyde resins were investigated with regard to the presence of 14 contact sensitizers by using high-pressure liquid chromatography. The allergens consisted of simple methylol phenols, dihydroxydiphenyl methanes, 4,4(1)-dihydroxy-(hydroxymethyl)-diphenyl methanes and 2,4(1)-dihydroxy-(hydroxymethyl)-diphenyl methanes. Four substances, 2,4-dimethylol phenol, 2,6-dimethylol phenol, 4,4(1)-dihydroxydiphenyl methane and 2,4(1)-dihydroxydiphenyl methane, were isolated from a resol resin and identified by mass-spectrometry and nuclear magnetic resonance spectrometry. The highest concentrations (up to 15% w/w) of allergens were noted for methylol phenols in resol resins based on phenol and formaldehyde. The corresponding novolak resins showed a high content of dihydroxydiphenyl methanes. There was great variation in concentration of the sensitizers between the resins. None of these sensitizers were demonstrated in the resin based on paratertiary-butyl phenol. Products based on phenol-formaldehyde resins were also investigated for the presence of allergens. Uncured impregnated paper for laminate production and uncured mineral wool contained the same concentrations of the sensitizers as some of the resins studied. The curing process decreased the content of all the allergens investigated in all products, but the sensitizers did not disappear, and they may thus be present in finished products.

Multicentre patch testing with a resol resin based on phenol and formaldehyde

“…Identifying the clinical relevance of any sensitizer is not standardized, and it would be necessary to have the capacity to analyse chemically the presence of the 14 separate individual sensitizers identified in PFR‐2, a task that very few centres in the world could perform. PFRs are known to be both irritants and potent sensitizers, and contain methylol‐substituted monomers and dimers, which are the major sensitizers (1, 7). As stated earlier, the common PTBP‐FR does not detect contact allergy to PFRs based on phenol and formaldehyde, and patients allergic to this latter resin will be missed if PFR‐2 is not tested.…”

“…A p ‐tertiary‐butylphenol‐formaldehyde resin (PTBP‐FR) has been included in most baseline patch test series for decades, but this resin does not detect contact allergy to phenol‐formaldehyde resins (PFRs) based on phenol and formaldehyde (1–4). Even though there are various resins based on phenol and formaldehyde, PFR‐2 (mixture of monomers and dimers from a resol resin based on phenol and formaldehyde) seems to be a good marker for contact allergy to such resins (1, 3, 5). In the past, it was shown that not only did patch testing with PFR‐2 detect patients allergic to the specific resol resin, but simultaneous allergic reactions were also seen to fragrance mix I (FM I), colophonium, and Myroxylon pereirae (6).…”

Occupational allergic contact dermatitis in a company manufacturing boards coated with isocyanate lacquer

“…5 out of a total of 20 machine operators were referred to our department and were patch tested with our standard series and isocyanates series. The standard series used at our department at the time comprised the European standard series excluding clioquinol, N‐isopropyl‐N‐phenyl‐4‐phenylenediamine, lanolin alcohol and supplemented with diazolidinyl urea, imidazolidinyl urea, thimerosal, methyldibromo glutaronitrile, phenoxyethanol, Euxyl K400, iodopropynyl butylcarbamate, DMDM hydantoin, gold sodium thiosulfate (1), palladium chloride, a resol resin based on phenol and formaldehyde (2), ethylenediamine dihydrochloride, lichen acid mix, tixocortol pivalate, hydrocortisone‐17‐butyrate, frullanolide, fusidic acid, caine mix II, tosylamide formaldehyde resin, a textile colour mix, Amerchol L‐101 and an epoxy resin based on diglycidyl ether of bisphenol F. The isocyanates series used comprised the isocyanate series from Chemotechnique Diagnostics, Malmö, Sweden, supplemented with dicyclohexylmethane‐4,4′‐diisocyanate (Aldrich Chemical Company Inc, Milwaukee, USA), synonymous with hydrogenated MDI (HMDI) and its corresponding amine, dicyclohexylmethane‐4,4′‐diamine (Fluka Chemie GmbH, Buchs, Switzerland), synonymous with hydrogenated 4,4′‐diaminodiphenylmethane (HMDA). The first 3 patients referred to us were also patch tested with the polyurethane lacquer used at the plant.…”

Routine Diagnostic Patch-testing with Formaldehyde 2.0% (0.6mg/cm2) may be an Advantage Compared to 1.0%

“…The described circumstances imply that the inclusion of any formaldehyde releaser in the baseline series should be based on the results of parallel routine testing with formaldehyde and the formaldehyde relcaser in question with optimized patch-test doses obtained with standardized patch-test techniques. There was no association between patients reacting to formaldehyde and the resins or plastics in which formaldehyde is used as a raw material, a phenomenon commented on in an earlier study (6).…”

“…At our department patch-testing with formaldehyde 2.0% has been used in patients with doubtful reactions to formaldehyde 1.0% and when there has been a strong suspicion of contact allergy to formaldehyde. For more than 25 years, defined micro-pipetted volumes have been used routinely at our department for patch-testing liquid solutions (6). According to our findings, 15 ^1 is optimal for the Finn Chamber technique (7).…”