ABSTRACT
Huntsman Polyurethanes (HPU) conducted a series of tests on aluminum and wood substrates cured with polyurethane glue and commercially produced composite boards cured with RUBINATE®(1) binder to evaluate MDI emissions.
The studies were performed in HPU’s AIHA accredited laboratory located in West Deptford, NJ.
Polyurethane glue was applied on wood boards or aluminum plates in different combinations (wood/wood, wood/aluminum and aluminum/aluminum), sandwiched together and tested at two temperatures, ambient (21° C) and 54° C. The wood boards and aluminum plates were tested for MDI emissions in a chamber that was flushed continuously for 40 hours with air. During this time, the air in the headspace of the chamber was sampled continuously for 40 hours, using Huntsman Sampling/Analytical Method I1024G revision 1.8. The filters through which the chamber air was drawn, were changed at every 8-hour interval for 40 hours. Five consecutive 8-hour samples were taken under each test condition.
Commercial composite board samples were cut to 5″ × 6″ test specimen and placed inside the test chamber and tested at two temperatures, ambient (23° C) and at 90° C. Dry air (at room temperature, 23° C) or dry nitrogen (at elevated temperature of 90° C) was flushed continuously through the chamber for over 48 hours. Both conditions were tested. During this time, the air in the headspace of the chamber was sampled continuously for 48 hours, using Huntsman Sampling/Analytical Method I1024G. revision 1.8. The filters through which the chamber air was drawn, were changed at every 8-hour interval for 48 hours. Six consecutive 8-hour samples were taken under each test condition.
The collected air samples were analyzed for MDI using a High Performance Liquid Chromatograph (HPLC). The limit of quantification (LOQ) for the analytical method referenced above is 20 parts per trillion (0.2 μg/m3 of air sampled). No MDI emissions were detected at the LOQ (<20 ppt) for all composite boards tested. For the aluminum and wood substrates cured with glue, MDI was detected at 60 ppt during the first 8-hour sampling. Subsequent 8-hour sampling results were below the LOQ (<20 ppt).
