Solidification and Gelling Issue of Plastisol Under Infrared Heater

Manufacturer: We observed something strange when trying to solidify and gel two different PVC plastisol compounds using oven with infrared heater. We thought they would both solidify within 20 minutes but we observed that while one gelled and solidified the other remained fluid.

However both plastisol compounds gelled and solidified satisfactorily when heated in an oven which is using electric heater. Can you explain why?

John Woon (Senior Latex Consultant): Unlike your electrical oven, infrared heaters depend on not only the wavelength it emits but also the substrate type i.e. the absorption characteristics of the substrate, e.g.
PVC plastisol.

Different IR heaters have different wavelengths. For instance, some IR heaters can't heat up water efficiently because the wavelength dose not match the absorption spectrum for water.

Apparently, the two PVC plastisol compounds have different absorption characteristics.