Well, in an attempt to quantify the actual exposure risk when using Resin X I decided to run a test. I want to make a disclaimer first. I am not a scientist, chemist, or representative of C3D in any capacity. I am just an amateur shaper with some access to this equipment through my family.
What I wanted to do is actually monitor the air quality in a confined space while preparing and using Resin X. So to simulate a “worst case” scenario I used a room 8’ x 12’ and turned off any active ventilation. The door was closed and the room had no windows opened. The Resin X I used was approximately 30 days old. This is important, because if I remember correctly from my organic chemistry classes, HDI monomer content can increase up to a certain percent by volume as the prepolymer sits on the shelf. I don’t know how much HDI monomer Resin X contains, but I know most modern isocyante activators used in urethane coatings dont contain much monomer anymore.
For reference the National Institute for Occupational Safety and Health (NIOSH) developed a REL for HDI monomer of 35 µg/m3 or 0.005 parts per million (ppm), but has not established a recommended exposure limit for the HDI prepolymer. The NIOSH REL is a time-weighted-average value for a normal working lifetime (up to 10 hours per day, 40 hours per week, for 40 years). NIOSH also established a ceiling value of 140 µg/m3 (0.020 ppm) for HDI monomer . A ceiling value is a concentration that should not be exceeded during any part of the working exposure; if instantaneous monitoring is not feasible, the ceiling must be assessed as a 10-minute time-weighted-average exposure for HDI monomer.
I know someone has been trying to scare everyone ranting and raving about how low the REL or TLV (TLV is actually a trademarked term) is for HDI but keep in mind that REL or TLV is a time weighted average for an entire working lifetime. Furthermore, keep in mind that the values are only for HDI monomer, not HDI prepolymer. An exposure limit for the HDI prepolymer has not been established by OSHA, NIOSH or ACGIH. Oregon is the only state OSHA program that has established an exposure limit for the prepolymer. Oregon’s 8-hour time-weighted average limit for HDI prepolymer is 500 µg/m3 (0.07 ppm) with a ceiling level of 1000 µg/m3 (0.14 ppm).
Someone claims that Matt is taking advantage of ‘surfers’ ignorance to chemical safety…who is really taking advantage of surfers’ ignorance to chemical safety with all the scare tactics. Sounds kinda like what the ‘industry’ did to a certain someone when he tried to get his new epoxy company off the ground…Lest we become what we despise.
Now back to the test…
The device I used is a Scott Instruments NextStep Gas Detection Monitor. It was set to continuous monitoring mode. I used an HDI cassette for this test, HDI is the isocyante found in Resin X. The machine was calibrated and found to be in accurate working order. It’s accuracy is +/- 20% of reading +/- 1 ppb. Its range for HDI is 0-500 ppb. I placed the monitor 3 feet from the table which I was working with the Resin X.
I first opened and poured 3 onces of Resin X Part A into a graduated plastic cup. I poured 2 onces of Resin X Part B into an identical graduated plastic cup. The air monitor continued to read 0 ppb. I then microwaved both parts in a small tabletop microwave until both parts of the Resin X read 95 degrees measured with a hand held inferred thermometer. I combined both parts and mixed for 20 seconds. The monitor still read 0 ppb. I then brushed the combined Resin X onto a 2x2 test panel I made, as if I was hotcoating a board. The monitor continued to read 0 ppb. I put the test panel on the table, disposed of the leftover Resin X properly, and left the room. I continued to left the monitor run for 1 hour while the Resin X cured. Still the monitor never recorded any HDI level over 0 ppb.
I concluded from these results that any free HDI present in the room is too low to be detected from the monitoring device I have. Trace amounts may exist, but I don’t have the high tech equipment require to detect such small quantities. Take this for what you want, but as far as I know its the only such test done so far. If anyone has any questions let me know. Thanks.
-Jon
