New Method Cuts Finish-Coat VOCs


A new gel coating used during manufacturing finishing could virtually eliminate the health and environmental risks of the organic compound styrene, researchers say.

Styrene is commonly used in the manufacture of plastics, rubber, and resins. The chemical is also known as vinylbenzene, ethenylbenzene, cinnamene, or phenylethylene.

Styrene vapors are emitted during manufacturing of fiber-reinforced polymer matrix composite finishes for products in transport applications, chemical plants, pipelines and renewable energy systems.

Now, researchers at Plymouth University in the UK have hit on a way to reduce styrene levels by more than 98 percent. The secret: an in-mold gel coating.

Linked to Altered Moods

Dr. John Summerscales, associate professor in Composites Engineering at Plymouth University, led the research.

"Styrene has been the subject of extensive debate in respect of health and environmental issues," said Summerscales.

"Exposure to styrene has previously been linked to altered mood states—in particular, aggression—while its vapor has been reported to cause depression, fatigue and a slowing in reaction times.

"By reducing styrene levels in the workplace, there would be numerous positive results, such as improving retention of workforce personnel, minimizing release to the environment, and reducing odor at the factory boundary," he said.

Another benefit, said Summerscales: keeping working conditions safe enough that employers are not tempted to ship the jobs to less-regulated countries.

Three Methods

The study compared three techniques used in the finishing process:

  • Conventional hand-painted gel-coating;
  • In-mold gel-coating with a separator fabric; and
  • In-mold surfacing with a silicone shim.

The hand-painted process had significantly higher levels of styrene emissions than the two closed-mold processes, the researchers found.

The open-mold process had styrene levels ranging from 28-70 parts per million (ppm). The two closed-mold technologies significantly reduced the styrene levels, to 0.23-0.37 ppm.

Lowering PPM

"The occupational exposure limits for styrene currently vary across the European Union, but a recent directive (REACH) is likely to result in the harmonization of permitted styrene levels—most probably at the current lowest (Scandinavian) level," said Summerscales.

He said the recommendation for a 20 ppm time-weight average (an 80 percent reduction in the UK) is "unlikely to be achievable with open-mold gel coating."

"The research we have undertaken aims to keep composites manufacturing within the EU, rather than exporting difficult manufacturing processes to less-regulated countries, with subsequent benefits for employment within European nations," he said.

European-wide Study

The full study, "Styrene emissions during gel-coating of composites," is being published in a November issue of the Journal of Cleaner Production.

John Summerscales Plymouth University
Plymouth University

"Exposure to styrene has previously been linked to altered mood states, in particular aggression, while its vapor has been reported to cause depression, fatigue and a slowing in reaction times," said Dr. John Summerscales, who led the research.

The work was part of the €1.4 million InGeCT project, "An innovative environmentally friendly gelcoating technology for composites in marine and wind-Turbine applications to reduce VOC emissions, processing time and cost."

The project was funded by the European Union's Framework Programme 7 (FP7) initiative.

InGeCt was a two-year research collaboration led by Plymouth University that involved academics and companies across Europe, including Alan Harper Composites in Cornwall, UK; Centro Tessile Cotoniero E Abbigliamento SpA in Italy; De IJssel Coatings BV in the Netherlands; KMT Nord APS in Denmark; Lightweight Structures BV in the Netherlands; SP Technical Research Institute of Sweden; and Tessitura Valdolona SRL in Italy.


Tagged categories: Coating Materials; Colleges and Universities; EMEA (Europe, Middle East and Africa); Europe; Health and safety; Polyester; Research; Styrene; Vinyl ester; VOC content

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