Improving the indoor air quality

The indoor air conditions and potential indoor air pollutants influence the health and comfort of people present. Volatile Organic Compounds (VOCs) are the most common indoor air pollutants. Coated materials used indoor may not exceed the maximum VOC content limit values. Low emission and also odour criteria have become key performance requirements. UV curable coatings are solvent-free but can give rise to remaining odours.
Rapid quality control using the FLEC

Ultraviolet (UV) curing is a surface treatment in which UV energy is used to cure an organic coating”, explains Veerle Van Lierde, Research Engineer Materials Characterisation & Testing at OCAS. “In some cases, UV curable coatings offer additional advantages, especially in hardness, gloss and resistance to scratching, abrasion and chemicals. Unlike conventional coatings, a typical UV coating contains oligomers and monomers, and is free of solvents. However, some residual products, such as non-reacted monomers and/or degradation products of photoinitiators, might remain in the film causing residual odour.”

“We performed a study for one of our customers on a steel sheet with a UV coating that emitted an odour after curing. The customer wanted to know whether this odour presented a possible health risk or not. To identify the compounds responsible for the remaining odour, we used our Field and Laboratory Emission Cell (FLEC), an easy-to-use device for sampling volatiles from materials - especially from coated panels - according to ISO 16000-10. VOCs are retained in a sorbent tube and then analysed using Thermal Desorption coupled with Gas Chromatography and Mass Spectrometry (TD-GC-MS), according to ISO 16000-6.”

Extensive range of laboratory techniques available at OCAS

Eliminating possible hazards

“According to specific Indoor Air Quality requirements, the UV coating investigated was not harmful. The amount of residual products was below the limit value so the coating was suitable for indoor use. This clearly illustrates the advantages of a lab-scale check prior to industrialisation: the influence of different parameters, such as the amount of photoinitiators, the UV dose and the thickness of the coating, can be tested in the laboratory first in order to easily optimise products and their associated processes. This way, it is even possible to develop coatings without any residual odour.”

“It is recommended to perform a risk assessment before launching a new product. Our extensive range of laboratory techniques (thermal desorption, GC-MS, FLEC, pyrolysis, etc) makes it possible to define the best product and process prior to industrialisation, ensuring a healthy and comfortable workplace environment.”