What are isocyanates and how can I best protect myself from them when painting?

By DuPont Personal Protection | Published: January 29, 2018

Isocyanates are powerful sensitizers and irritants that can cause serious health effects as a result of dermal and respiratory exposures. They are contained in some types of paints and coatings. Other coating constituents can also have significant health hazards associated with them. Some types of paint present risks not only when applying the paint, but also when preparing the paint or cleaning tools, using solvent washers, and so on.

Your choice of protective clothing fabric should be based on an evaluation of the available permeation data for the paint constituents or cleaning solvents being used. Permeation refers to a chemical material's absorption, diffusion, and desorption through the barrier material of protective clothing at the molecular level. Penetration, on the other hand, is the passage of a chemical through a pore or opening in the barrier material.

So, in plain terms, what is the difference between permeation and penetration? Consider this example. Have you ever opened an old bottle of soda and discovered it was flat? There aren't any holes in the bottle. The liquid is still inside. So why is the soda flat? It's flat because the carbon dioxide

that gives soda its fizz has permeated through the walls of the bottle over time. But if you grabbed a fresh bottle of soda, opened it, and did not replace the cap, the carbon dioxide would just escape out of the top of the bottle. That would be penetration.

Permeation tests are better suited for testing hazardous liquids and vapors, such as isocyanates. Based on the permeation data for the hazard, a higher level of barrier protection may be needed, along with taped seams to provide strong chemical resistance against heavy liquid splashes. Tychem® fabrics, for instance, provide a higher level of liquid chemical permeation resistance for potentially hazardous tasks. These fabrics are appropriate for situations in which the wearer could face prolonged exposure to un-reacted activators or solvents, such as in the maintenance of large-scale paint distribution equipment, spill cleanup, or large volume mixing activities (for more advice, see Looking for the Right Protection for Painting?).

Learn more about painting and the hazards that painters face in DuPont Personal Protection’s upcoming webinar: Are You Sure Your Painters Are Fully Protected?, Thursday, February 1st, 1pm ET.

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