3.Machining and processing HPL
HPL compact with a colored core is suitable for special interior design applications that require low material thickness with high strength and consistent, uniform coloring. For washbasins or sinks, a decorative color connection can be achieved by bonding directly under the HPL with color core. Striped effects can be achieved by using different colored paper layers. These are used, for example, in engraving material for nameplates, labels, and signs of all kinds, or serve as decorative edge designs.
A dark or black layer of phenol-resin saturated core papers is usually visible on HPL. On HPL with coloured core, the colour of the core can match the surface or provide a contrast. HPL with colour core is described in part 9 of EN 438. The surface and the core consist of melamine-resin impregnated and white or colour-pigmented cellulose sheets.
HPL with coloured core has to be machined and used in the same way as HPL or HPL-Compact, but usually is more brittle. This applies e. g. to the resistance to temperature, scratching, abrasion and impact, light fastness and many other physical properties. Certain limitations apply with regard to machining by sawing, milling / routing and sanding. It also has to be taken into account that the shrinking and swelling behaviour is greater than in normal HPL and HPL-Compact.
For HPL composite elements, it is common to use HPL as edge material with a thickness up to 3 mm. For surface coating, a completely symmetrical structure of the HPL composite element (in terms of type, thickness, and color of the HPL) has proven successful. Beyond this, the running direction (sanding direction) of the HPL on the front and rear sides has to be the same.
Edge material
For thicker edges on HPL with coloured core, it is quite possible to continue the milled radius of an HPL/HPL composite element in the fully coloured edge material to produce a visually appealing result:
1 Uniformly coloured HPL
2 HPL with differently coloured core
