Low VOC epoxy resins = safe resins?
Every epoxy manufacturer and distributor likes to state that their products are low VOC. As a matter of fact, the low VOC claim or badge on the package is often seen as a certificate of quality and safety of the product. No doubt, the absence of chemicals emitting from your resin art piece is great, but is this all that resin enthusiasts should care about? How accurate is this approach and loud low VOC claims in reality?
VOC as Volatile Organic Compounds
Chemical compounds with high vapour pressure (ability to evaporate easily) are called volatile organic compounds. Xylene, Naphtha, Toluene, Isopropyl Alcohol and others are common examples of VOC. Environmental and health concerns led to imposed regulations on the percentage of certain VOCs in materials that can be used in the construction/painting industries. However, these chemical compounds still are irrepressible in many applications such as chemical synthesis, cleaning and composite fabrication. Petroleum fuel, for example, is made with more than 30 types of VOCs. The smell of a new car is also made entirely of VOCs emitting from plastic panels.
VOC in Epoxy Resins
Historically, the majority of epoxy systems are used in industrial coatings such as floor or pipeline coating applications. Formulators use the volatiles to give the desired performance characteristics, such as low viscosity, the ability to spray the compound at certain thickness levels, predictable curing time. For example, solvents like acetone can significantly prolong the pot life of the epoxy flooring system by reacting with part B of the epoxy. Once the resin is applied, this reaction reverses, giving extra time for levelling and air-release.
After the epoxy is applied to the substrate, most of the volatile content evaporation happens in the first hours and gradually slows down in the next few days to a week.
Low or zero VOC = Safe product?
Let's try to dig into the word "safe" and understand what it means in our case. There is no 100% safe epoxy available on the market, period. Statements such as "Low VOC & Safe for Home Use" emphasize too much attention on the volatile compounds but miss the elephant in the room.
It is true that volatiles, often used in paints or industrial coating systems, possess certain danger to health, the respiratory system in particular. However, it does not mean that VOC-free products are safe to breathe in! For example, certain chemicals are VOC exempt, like benzyl alcohol; even though it is a volatile. Other chemicals in epoxy resin composition can be volatile enough and dangerous to the respiratory system, but not considered to be VOC because they participate in chemical reaction. Such chemicals still cause harm to the respiratory system, look up the nonylphenol or butyl glycidyl ether.
Butyl glycidyl ether is used in epoxy resins to reduce the viscosity of product. The component is not commonly considered as a VOC but possess serious health hazards.
How to choose the right product for home use?
Best epoxy resin or pigment for home use should have the following:
- Contain no VOC and compounds that cause respiratory irritation or are toxic if inhaled.
- Be nonylphenol-free (some manufacturers hide the fact of nonylphenol usage by naming it differently, amine adduct, for example. Ask your brand representative for a specific compound name. Chemicals in concentrations >1% are not considered to be a trade secret and a distributor must tell you what the product is made of.
- Safety Data Sheets that must be easily accessible for your review before product use.
- Proper labeling (safety pictograms and composition of the product) should be in place.
- Proper packaging including child-resistant closures must be present.