Knowledge and Experience
In the wood-based panel industry, regarding surface finishing, impregnation is the key process that enables all kind of papers to be loaded up with the exact amount of thermosetting resin for it to react during subsequent pressing operation. Resins used are primarily melamine (melamine – formaldehyde), while a proportion of urea resin (urea - formaldehyde) can also be present. Kraft papers are usually impregnated with phenolic resins (phenol – formaldehyde).
The impregnation process is performed continuously on lines that are provided with an immersion bath in which the paper is accurately and uniformly saturated with liquid resin before metering rolls remove excess material and drying ovens evaporate the proper water quantity. Following impregnation, the papers have usually more than twice as much weight. Knowledge and experience are a must to design and manufacture an efficient and well-performing impregnation station.