Diisocyanate Emission from a Paint Product: A Preliminary Analysis

Abstract

Exposure of workers to diisocyanates in the polyurethane foam manufacturing industry is well documented. However, very little quantitative data have been published on exposure to diisocyanates from the use of paints and coatings. The purpose of this study was to evaluate emission of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate (2,6-TDI), and isophorone diisocyanate from a commercially available two-stage concrete coating and sealant. A laboratory model of an outdoor deck coating process was developed and diisocyanate concentrations determined by derivatization with 1-(2-methoxyphenol)-piperazine and subsequent high performance liquid chromatographic analysis with UV detection. The detection limit for 2,4-toluene diisocyanate and 2,6-toluene diisocyanate urea derivatives was 0.6 microg TDI/gm wet product, and 0.54 microg IPDI/gm wet product for the isophorone diisocyanate urea derivative. No 2,4-toluene diisocyanate or isophorone diisocyanate was detected in the mixed product. A maximum mean 2,6-TDI emission rate of 0.32 microg of 2,6-TDI/gram of wet product applied/hour was observed for the 1-hour sampling time, 0.38 microg of 2,6-TDI/gram of wet product applied/hour was observed for the 5-hour sampling time, and 0.02 micrpg of 2,6-TDI/gram of wet product applied/hour was observed for the 15-hour sampling time. The decrease in rate of 2,6-TDI emission over the 15-hour period indicates that emission of 2,6-TDI is virtually complete after 5 hours. These emission rates should allow industrial hygienists to calculate exposures to isocyanates emitted from at least one curing sealant.

Characterization of methylene diphenyl diisocyanate-haptenated human serum albumin and hemoglobin

“…These analyses should include (1) measurement of amount of diamine/mole HSA following acid hydrolysis, (2) TNBS measurement of cross-linking, (3) denature gel electrophoresis for indication of intermolecular and intra-molecular cross-linking, and (4) use of mAb for antigenicity standardization. Both qualitative and quantitative differences in MDI binding were observed between Hb and HSA conjugates suggesting normalization to conjugation ratio is not sufficient to compare antigenicity of different diisocyante haptenated proteins.…”

“…Exposure to dNCO has most commonly been reported in the occupational setting (3;4); however, concern of potential exposure through leaching of dNCOs from cured, semi-cured or non-cured products has recently been raised in domestic settings(5). …”

“…In the present study, MDI was reacted with human serum albumin (HSA) and hemoglobin (Hb) at molar ratios ranging from 1:1 to 40:1 MDI: protein. Adducts were characterized by (1) loss of available trinitrobenzene sulfonic acid (TNBS) binding to primary amines, (2) electrophoretic migration in polyacrylamide gels, (3) quantification of methylene diphenyl diamine following acid hydrolysis and (4) immunoassay. Concentration dependent changes in all the above noted parameters were observed demonstrating increase in both number and complexity of conjugates formed with increasing MDI concentration.…”

Do indoor chemicals promote development of airway allergy?

“…Their role in development of non‐occupational asthma is not entirely clear. However, emission of isocyanate ceased within 5 h after the application of an isocyanate paint (Jarand et al., 2002) and emission also had a fast decay of isocyanates from polyurethane adhesives (Wirts and Salthammer, 2002), which suggests mainly occupational exposures. Overall, few VOCs have been identified as allergenic (Becher et al., 1996).…”

Viability of cultured human skin cells treated with 1,6-hexamethylene diisocyanate monomer and its oligomer isocyanurate in different culture media

“…The annual production of isocyanates worldwide was about 4.4 million metric tons in 2002 4 and, currently, an estimated 440,000 workers are exposed to isocyanates in the United States 5 – 7 . Exposures in the general population can occur from contact with isocyanate-containing consumer goods (e.g., Gorilla glue ® ), slow-curing isocyanate coatings, materials used in housing construction, in outdoor areas near industrial sites where isocyanates are used in manufacturing, or in neighborhoods surrounding auto-refinishing businesses 8 – 10 . While inhalation exposure to isocyanates has been considered the most important route through which allergic sensitization may occur, animal studies have shown that skin exposure can result in respiratory sensitization 11 , 12 .…”