Protecting Yourself from Isocyanates

Isocyanate is a dangerous chemical, so have a good spray booth and wear full protective gear. October 19, 2013

Question
I plan on using 2K poly's and I am buying a fresh air respirator because of the isocyanates. One thing I am not clear about is when the iso's are present in the air. If I spray in the booth and carry the work piece in the drying room will the iso's still be in the drying room where the pieces are curing, or just the booth where the airborne particles are located? I am just asking so I know whether or not I need a fresh air mask when I go into the drying room. Or should I just wear it when actually spraying?

Forum Responses
(Finishing Forum)
From contributor F:
I would wear the mask. I was told by MLC to wear one when mixing Euro bild or EuroX because of the iso's.

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From contributor O:
You should double check this with your finish supplier but I’ve been told (if I am remembering this correctly) that the iso's are absorbed by moisture in the air so they are pretty much gone when you are done spraying. I've also heard the same thing about mixing and wearing a mask. Please report what you find. Many of us are interested in exploring this finish and want to do it as safely as possible.

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From contributor A:
I consider myself no chemistry expert either but it seems to me everything we use in the business of spraying coatings is extremely hazardous and it is incumbent on all of us to understand the particular risks of any given product. Then we pick our poison and protect ourselves accordingly.

It’s puzzling to me how the 2k Urethanes using isocyanate hardeners dominate the scene in European countries where formaldehyde containing coatings are out of favor if not banned. Here in the States coatings that use an acid catalyst and off gas loads of formaldehyde are still the preferred poison of the day. The priority that seems out of sorts to me is how so many finishers worry about the dangerous materials they use, but seem unwilling to invest in the most important safety feature of all - a quality engineered spray booth and air makeup. That should be job one. The rest is manageable. Otherwise it doesn't much matter whether you prefer formaldehyde to isocyanates or vice versa.

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From contributor C:
I used to spray cars for twenty years. You can definitely get exposed to iso's while standing near, or entering a drying room where freshly painted pieces are curing. In tech school we were told that the next day after an air cure we are still getting some (I don't know how much) iso's while buffing a finish. I would set up a fan to blow across the surface while I was buffing a car. Don't take any chances with iso's.