Development of innovative, marketable products with improved material properties made from hard-to-impregnate native softwoods using a novel perforation process for wood impregnation
In this cooperation project, an innovative perforation process for wood impregnation with wood preservatives was developed for softwoods that are difficult to impregnate. One of the main goals of the project was to develop a perforation process with appropriate aesthetics and to achieve high and uniform penetration depths of wood preservatives in order to meet the requirements of use class NP 3 (insect-resistant, fungus-resistant, weather-resistant, moderately fungal resistant) DIN 68800-3 (2012). The idea was to press tiny holes in the wooden surface in a tight grid; i.e. to "perforate" the wood to a desired depth (about 1 cm). The wood was fed between driving rollers and perforated by spring-loaded needles. Thus, an almost continuous impregnation was achieved in the subsequent preservative impregnations. Furthermore, during the course of this research project, it was possible to prove that the perforations and preservative treatments are also suitable in combination with visually appealing oily or hydrophobic surface treatments for the production of solid wood products (garden wood, deckings, claddings, etc.). Significant material improvements in terms of weathering and UV stability could also be demonstrated.