Surface treatment of Solidiwood products

The uniform, dense surface of a Solidiwood product and the film of resin and extractives that forms on it repel moisture, dirt and decay even without surface treatment.

An alternative to applying the coating to the blanks as a liquid is to apply it as a film coating.

The costs of coating consist of the coating agents or films and of the equipment required for applying them and its operation.

Solidiwood process technology carries out the pressurised treatment of the blanks both with the wood’s own binders and with added treatment chemicals/materials selected from impregnating agents, fillers/primers, surface-treatment agents and adhesives/films/scrims. Special possibilities that also deserve mention are the use of melamine, plastics and nano-scale cellulose fibrils.

By means of pressing and binding/coating agents, the surface treatment enables the densification and homogenisation of the product’s surfaces, the repair of defects, and a pressure-impregnation-like surface treatment of the product.

Coatings can even be pressed in several layers on top of each other to create a sandwich structure.

Solidiwood treatment makes it possible to apply agents, each in the specific type and quantity required, to all surfaces of the blank or only to those that need them. By pressing, as much agent can be brought into the surfaces where necessary as the pressing pressure permitted by the product can force into the inhomogeneous wood. This also allows the use of thicker, more paste-like agents. Cavities, broken knots, cracks and other similar defects in the wood surfaces can thus be filled and sealed.

When the pressing batch is changed and when the pressing process is interrupted, the removal of coating residues is carried out where necessary.

Liquid coating of Solidiwood products can be applied to all surfaces or only to some of them. The coating on each surface can also be different.

Coating agent or water is also needed to soften the surface, e.g. to obtain an exceptionally smooth surface.

Solidiwood liquid coating could offer the plywood and hardboard industry a more economical alternative to its film coating. The same would apply to the coating of CLT, LVL and Solidiwood elements.

Manufacturers of films for the wood-based panel industry can also produce tubular ‘sock’ films. In the Solidiwood process, they can be used, for example, to encase the exterior cladding boards of an apartment building requiring particularly strong fire and other protection in even several sock-film layers containing protective agents. Of course, strong protection can also be achieved solely with different layers of liquid protective agents.

In the Solidiwood process, all film coatings are drawn onto the surfaces of the blanks from a roll assembly at the outfeed or infeed end of the press. Each press level has its own film-roll shaft, and the shafts are at a sufficient distance from each other and likewise from the press.

Film coating can be reinforced with a scrim placed under the film or between two films.