Dharmarajan V, Lingg R D, Myer H E
Bayer Corporation, Pittsburgh, Pennsylvania, USA.
Appl Occup Environ Hyg. 2001 Mar;16(3):397-404. doi: 10.1080/10473220117074.
Hexamethylene diisocyanate (HDI)-based polyisocyanates are widely used in formulating polyurethane coatings. These polyisocyanates contain a small amount of HDI monomer and the American Conference of Governmental Industrial Hygienists (ACGIH) recommends an eight-hour time-weighted average (TWA) threshold limit value (TLV) of 5 ppb for HDI. Some polyurethane (PU) paint applicators have used air-purifying paint spray respirators with organic vapor cartridges and particulate pre-filters. In this study, the effect of typical paint solvents on the efficiency of organic vapor cartridges (OVC) for HDI vapor was tested. A Teflon-coated polycarbonate exposure chamber was constructed. Three OVCs were simultaneously tested in an atmosphere containing HDI vapor and solvents. The test atmosphere was generated by evaporating a mixture of paint solvents containing n-butyl acetate, propylene glycol mono methyl ether acetate, toluene and methyl ethyl ketone, and neat HDI. The target challenge concentrations were 20 times the TLV for HDI and 10 times the combined TLV for the solvent mixture. The test atmosphere, with 20 or 80 percent relative humidity and at room temperature, was drawn through each cartridge at 32 L/min for 40 hours. However, in the last 8 hours of the test, the atmosphere had only HDI vapor. The pre- and the post-cartridge atmospheres were periodically sampled for HDI and the solvents. The study concluded that under the test conditions there was no detectable breakthrough of HDI from the OVCs. The average calculated efficiency of the OVCs, based on the HDI analytical limit of quantitation, was >99.4 percent for the 40 hours tested. The overall average challenge concentration of HDI was 105 ppb and the average combined solvent concentration was 3,176 mg/m3. The cartridges were saturated with solvents within the first 10 hours of testing; nevertheless, continued challenging with HDI vapor and solvents did not show any HDI breakthrough. Solvent breakthrough and breathing resistance, rather than HDI breakthrough, would be the key parameters in life expectancy calculations for cartridge change out schedules.
基于六亚甲基二异氰酸酯（HDI）的多异氰酸酯广泛用于配制聚氨酯涂料。这些多异氰酸酯含有少量HDI单体，美国政府工业卫生学家会议（ACGIH）建议HDI的八小时时间加权平均（TWA）阈限值（TLV）为5 ppb。一些聚氨酯（PU）油漆施工人员使用了带有有机蒸气滤毒罐和颗粒前置过滤器的空气净化喷漆呼吸器。在本研究中，测试了典型油漆溶剂对HDI蒸气有机蒸气滤毒罐（OVC）效率的影响。构建了一个涂有特氟龙的聚碳酸酯暴露室。在含有HDI蒸气和溶剂的气氛中同时测试了三个OVC。测试气氛是通过蒸发含有乙酸正丁酯、丙二醇单甲醚乙酸酯、甲苯和甲乙酮的油漆溶剂混合物以及纯HDI产生的。目标挑战浓度为HDI TLV的20倍和溶剂混合物组合TLV的10倍。在20%或80%相对湿度以及室温下的测试气氛，以32 L/分钟的流速通过每个滤毒罐40小时。然而，在测试的最后8小时，气氛中仅含有HDI蒸气。定期对滤毒罐前后的气氛进行HDI和溶剂采样。研究得出结论，在测试条件下，没有检测到HDI从OVC中穿透。基于HDI分析定量限计算的OVC平均效率在测试的40小时内>99.4%。HDI的总体平均挑战浓度为105 ppb，溶剂的平均组合浓度为3176 mg/m³。滤毒罐在测试的前10小时内被溶剂饱和；然而，继续用HDI蒸气和溶剂进行挑战并未显示出任何HDI穿透。溶剂穿透和呼吸阻力，而非HDI穿透，将是计算滤毒罐更换时间表预期寿命的关键参数。
