Zero joint - Technological principles

How does the zero joint adhesion work?

The well-known hot-melt adhesive process uses edgebanding material made of plastics, paper or veneer. This is either pre-coated with a layer of hot-melt adhesive or is glued to the panel material by applying heated, liquid hotmelt. Coloured adhesives are used to keep the transition between edge band and panel as invisible as possible. However, their colour spectrum is limited.

The zero-joint gluing method works with an edge made of two layers: The carrier material, which is visible from the outside, and the functional layer. This functional layer is applied during the production of the carrier material. The base material and the functional layer have one and the same colour. This promotes the impression that the edge and the workpiece are cast from the same mould.

When the edge is glued to the workpiece, the functional layer is melted directly where the edge meets the workpiece by a bundled and directed heat supply. The pressure rollers of the gluing machine press the edge with the liquid functional layer against the narrow side of the workpiece. The functional layer penetrates into the pores of the workpiece and seals them completely. In the ideal case, all spaces between the actual edge and the workpiece material are filled with the functional layer. Then steam and liquid water in the edge area have no possibility to penetrate into the panel material. A high tensile strength results from the multiple anchoring of the functional layer in the pores of the workpiece and the insolubility of the edge material and functional layer. The high melting point of the functional layer (125 °C and higher) guarantees good heat resistance.

Various methods for heat generation have been established, for which the functional layer can be adapted in each case.

Zero-joint gluing can be carried out with manual edge banding machines, automatic edge banding machines and CNC-machining centres.