Zero joint - Functional layer

The functional layer - what is special about it?

The functional layer forms the basis of the zero joint technology. It is adapted to the respective technical method, the respective edge and the respective colour. The functional layer is extruded onto the reverse side of the edge during the production of the edgeband or applied subsequently. Co-extruded edges require a higher heat energy for melting than the subsequently coated edges. With subsequent coating, edgebanding manufacturers can react flexibly to the variety and deadline requirements demanded by the artisanry.

What does the functional layer consist of?

The functional layer is often produced on the basis of polyolefin (PO). These are semi-crystalline plastics, which also include, for example, polypropylene (PP) used for edgebandings. EVA- and PU-based functional layers are hardly used or only used in certain colours in laser and hot air technology. In the case of functional layers for laser technology, absorber particles are added which promote energy absorption.

What is the difference to conventional pre-coated edge material?

Put simply, conventional pre-coated edge material consists of a veneer or plastic edge and an EVA hot melt adhesive layer. EVA has good adhesive properties, it is resistant in many ways and it is stretchable. However, it has a slight tendency to shrink.

The functional layer of the zero-joint edges consists of the same semi-crystalline and dimensionally stable plastics as the edgeband itself, but is optimised to absorb a lot of energy in a short time. They thus react to the directed and bundled energy supply of the zero-gap gluing units with melts, whereas the edgeband itself retains its solid state of aggregation.

The advantage of the zero-joint-"joint" compared to opposite is that it is filled with a material that is resistant in its shape, does not shrink and therefore does not allow any dirt to penetrate.

Patent rights have led to the development of miscellaneous technical method of energy release in the zero-joint gluing units. Each type of energy emission places different demands on the property the functional layer. For this reason, the edgebanding manufacturers, in cooperation with the machine manufacturers, have optimized the functional layer for the respective technical method. The following chapters deal with the miscellaneous technical methods of energy emission.

Images

Functional layer from Ostermann
2014
optical zero joint
2013