The infrared drying method of water-based varnish uses a light source that can emit energy in a very narrow wavelength range (IR range) to heat the coating film that can absorb radiation in this wavelength range. This method reduces the drying time of water-based coatings, as the wavelength of the infrared radiation has a significant effect on drying water-based coatings. Infrared heat is important for water-based coatings as it allows for faster removal of the water, resulting in less fibre swelling in varnishes on wood materials or printing materials.
The infrared drying process has several disadvantages. One of the main disadvantages is the higher electricity cost compared to other heating methods such as wood or gas. Additionally, it can be challenging to dry and cure parts of various sizes and densities since convection ovens are difficult to control. Furthermore, there is a delay in the initial rising temperature due to the time it takes for infrared radiation to heat up. Lastly, there is a risk of creating ‘hot spots’ and ‘cold spots’ during the drying process due to uneven heating from infrared radiation.