Industrial Convection Dryers
For the converting industry, various web converting drying methods can be selected to achieve efficient and uniform drying while maintaining the integrity of the substrate to produce defect-free products.
Industrial convection dryers involve passing the web through a drying chamber where heated air is impinged onto the surface of the coated substrate, evaporating moisture or solvents from the coating. Temperature, airflow velocity, and residence time are critical parameters that are carefully controlled to ensure effective drying without damaging the substrate.
Infrared Dryers
Infrared (IR) drying uses infrared radiation to heat the web and evaporate moisture or solvents. IR lamps emit electromagnetic waves with wavelengths tailored to efficiently penetrate the material and generate heat within the substrate. IR drying is particularly effective for drying thick coating.
Curing Process
After drying, the coated web may undergo a curing process to further enhance the
properties of the coating. Curing involves chemical reactions such as cross-linking or polymerization, which is triggered by exposure to heat, UV light, electron beams, or other energy sources. The choice of curing method depends on the type of coating and the desired properties.
In heat curing, the coated web typically passes through outfeed sections of the dryer where it is exposed to elevated temperatures for a specified duration. This allows the coating to undergo thermal reactions, leading to cross-linking or polymerization. The temperature and residence time in the oven are optimized to achieve complete curing without causing substrate or coating damage.
UV Curing
UV curing involves the use of ultraviolet (UV) light to initiate photochemical reactions in the coating formulation. The coated web passes under UV lamps, which emit high-intensity UV light at specific wavelengths tailored to activate photoinitiators in the coating. Electron beam (EB) curing utilises a beam of high-energy electrons to initiate curing reactions in the coating.
Drying Methods
Each of these drying techniques offers unique advantages and is selected based on
multiple factors such as the substrate material, coating formulation, coating thickness, production speed, desired properties of the final product, to name a few.
Drying is also involved in several industrial batch processes, helping to remove moisture content from coatings and various substrate materials, across numerous applications.
Pyradia manufactures a complete range of convection dryers, infrared dryers and
combination dryers, and more. Rely on Pyradia expertise to select the ideal dryer for your application
