Testing of household products and materials for emission of toluene diisocyanate.

Polyurethane products were subjected to chamber testing to determine their emission rates of 2,4- and 2,6-toluene diisocyanate (TDI). The polyurethane (PU) products included carpet padding, furniture cushions, sheet foam, varnishes, and sealants, as well as a commercially-applied water sealant product for concrete that contained up to 4 percent TDI by weight. The PU products were screened in a 9-L glass chamber, under elevated temperature and chamber loading conditions, using both a time-integrated sampling and analysis method specific for TDI and a continuous but non-specific real-time monitor for isocyanates. None of the products normally found in residences showed a positive response in the screening tests, indicating that TDI emissions and consequently toxic effects from such products are negligible. However, the commercially-applied water sealant gave a positive response in the screening test. Further testing of that product at realistic temperatures showed initial TDI emission rates of about 300,000 micrograms/m2/hr, with emissions lasting only one hour or less. At 21 and 27 degrees C, about 1 percent and 5 percent, respectively, of the TDI content of the product was released to the air. The emitted TDI was predominantly the 2,6-isomer, although the TDI originally present in the product was predominantly the 2,4-isomer.

Degradation of polyurethane foams used in the Même breast implant.

The release of toluene diisocyanate derivatives from polyurethane foam covers that were removed from the Même breast implant was studied. The polyurethane foam covers as retrieved from the implants were contaminated on average with 2,4- and 2,6-toluene diamine (TDA), 2,4- and 2,6-toluene diisocyanate (TDI), and toluene isocyanate amine (TIA) at the 1086 ppm level (combined TDA, TDI, and TIA). When cleaned foam was incubated in Ringer's solution at 37 degrees C for periods ranging from 6-35 days, 4.6 ppm/day of TDA, TDI, and TIA (combined) was formed; the projected annual degradation rate of the foam under these conditions was estimated to be about 0.8%. When cleaned foam was incubated dry at 37 degrees C, 1.5 ppm/day of TDA, TDI, and TIA (combined) was produced. Hence, the polyurethane foam covers used in the Même breast implants are susceptible to both thermal and hydrolytic degradation under simulated physiological conditions.

Trace analysis of airborne aromatic isocyanates and related aminoisocyanates and diamines using high-performance liquid chromatography with ultraviolet and electrochemical detection.

A high-performance liquid chromatographic method was developed for trace analysis of complex air mixtures containing 2,6- and 2,4-toluenediisocyanates and related aminoisocyanates and diamines. The accuracy was tested at isocyanate concentrations of 2-1000 microg/m3 in air. The method is based on derivatization in the sampling step of isocyanate functions to corresponding urethane groups, with alkaline ethanol as the sampling and reacting medium. The derivatives formed, toluenediurethanes and tolueneaminourethanes, and unreacted diamines were detected by UV or electrochemically, the electrochemical detection being one order of magnitude more sensitive. Using an enrichment column, detection limits of ca. 0.05 pg/microl were obtained with electrochemical detection at a potential of 950 mV, which corresponds to air concentrations of 0.1 microg/m3 with 5 min sampling time at a rate of 11/min. The precision in the measurements were ca. 4% at concentrations of 6 microg/m3. A field measurement was performed concerning flame lamination of toluenediisocyanate-based polyurethane and cloth. Isocyanates, aminoisocyanates and diamines were found at air concentrations of 1-100 microg/m3.

Allergic contact dermatitis to a photopolymerizable resin used in printing.

Organic photopolymerizable resins increasingly used in printing make it possible to produce flexible, lighter plates. A certain number of skin lesions and general symptoms appeared upon manipulation of plates made by the Letterflex process. In the workshop where this study was carried out, 12 out of 15 people suffered various degrees of skin lesions. The epicutaneous tests and biopsies performed indicate an allergic type reaction to one of the resin's constituents, polythiol. Experiments with animals confirm the strong allergenicity of this compound.