1.2.4Impregnation

Kraft and decorative papers are supplied in large rolls from approx. 0.5 t. In horizontal and continuously operating impregnation plants, the paper is unwound and immersed in the resin bath to saturate it with resin. Suitable rollers or scrapers remove the excess resin. Then the wet paper is suspended in the drying oven (approx. 15 – 25 m long) and dried in a stream of hot air (approx. 130 – 200 °C). Melamine resin impregnation machines operate with a feed rate of approx. 15 – 25 m/min, and with 50 – 250 m/min for phenolic resin impregnation. The air stream is purified through afterburning to prevent emissions into the environment. The heat energy in the hot air is recovered. The dried impregnated material, with still reactive resin, is cut to the required lengths or rolled up again and stored in conditioned rooms for subsequent further processing.