TGIC: A good idea turns toxic

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How many times have you done something ‘green’ and found out that your good intentions had unintended consequences? I recently fell victim to a potentially dangerous misconception.

As part of my objective to eliminate the use of solvent based paints at Sun Microsystems, I began to move toward very low-VOC (volatile organic compound) water-based paints and powder coatings. Powder coatings seemed to be one of the most green options. Powder coatings are inert, can be applied efficiently, the waste material is easy to recover and is not considered a VOC. I have been to many powder lines and have seen applicators spraying powder while wearing no dust masks or other safety gear. Then I heard about TGIC (triglycidyl isocyanurate).

TGIC is a low-molecular-weight, multifunctional crosslinker which enables polyester TGIC formulations to contain 90% or greater resin within the binder system. Because they enhance the weather-resistance of polyester, TGIC coatings are comparable to polyester urethane coatings. They also offer faster or lower temperature curing than polyurethanes, and unlike urethane coatings, TGICs maintain excellent mechanical properties at film builds above 3 mils – with no outgassing. Additionally, TGIC coatings provide superior coverage of sharp edges – that’s important in the manufacture of computer components. Sounds good right?

So what’s wrong with TGIC? It nicely enhances the coatings and improves coverage. The issue is that it is TOXIC. TGIC is a Category 2 mutagen. As a result it is now classified as a toxin and cannot be used in certain regions. TGIC is known to cause skin sensitization in some people, which can lead to severe skin rashes. Respiratory sensitization is also a concern.

Exposure occurs by breathing in dust containing TGIC, by skin contact and by ingestion. Ingestion can be caused by contamination of hands, food and drink, and following inhalation. As a result beginning this year many companies in the European Union have stopped applying this material, and this practice will propagate to other regions as well.

So what can we do? There are other options available. The safest bet is to specify TGIC-free powder. While TGIC will likely be your supplier’s first choice for a durable coating, there are other options like Primid [2], and PT910 (currently under review in the EU). We are learning significantly more about base chemical toxicity through the works of groups like MBDC [3] and others. Still, as designers, we need better tools, and we need a community to share information to help us make better choices. It is my hope that through tools like those provided by Sustainable Minds we can better educate designers and also build a database of knowledge that will lead to a better future.

If you are aware of processes or materials that may only be green under certain conditions, or are new and exciting options to traditional materials, I ask you to please respond to this post with your comments and findings.

Design a better future.