Doellken PVC Edgebands may be processed using hot melt adhesive techniques on all edgeband gluing machines (straight processing and machining centers). Gluing, cross-cutting, milling, scraping and subsequent buffing with polishing wheels and hot-air dryers for high quality surfaces poses no problem. To ensure clean and durable edgeband finishing, certain important processing parameters which may be dependent on materials used (edgebands, adhesive, boards), on the edgeband gluing machine and on ambient temperature, must be observed. Trials to determine relevant optimal settings are therefore recommended. Manufacturers’ guidelines for an intended application should also be considered.
Doellken PVC Edgebands may be processed using any standard hot melt adhesive (EVA, PA, APAO, PUR). Used in combination with the low-shrink raw material formulation of Doellken PVC, highly heat-resistant adhesives can guarantee reliable bonding even on edgebands thicker than 3 mm. Particularly heat-resistant adhesives are recommended for applications exposed to high temperatures, e.g. near kitchen ovens or for furniture exported in containers. Doellken PVC Edgebands exhibit very low “free shrinkage” before gluing already. Another positive feature is the dimensional stability of PVC Edgebands: The material starts softening only after 80 (± 2)°C (Vicat B 50). Ensure that the container has sufficient glue to maintain a constant temperature during application. The glue application temperature will vary between 90°C and 220°C, depending on the type of adhesive. Please note that thermostats in hot melt hoppers are often inaccurate and may deviate considerably from the actual temperature on application rollers. It is advisable to measure the temperature on the application roller. Doellken PVC Edgebands cannot be glued using PVAC glue and the cold activation method.
For best results fitting edgebands, work with boards and edgebands at room temperature (not below 18°C). Material stored outdoors should be warmed up overnight. Hot melt glue will cure before the edgeband is in place if the temperature of the board or edgeband is too low. Draughts should for this reason also be avoided.
The optimal moisture content of the boards should be between 7 and 10% for further processing.
The special raw material formulation of Doellken PVC Edgebands is designed for feed rates both in low as well as high volume processing. Depending on the edgeband gluing machine, speeds between 10 and 100 m/min. are possible. Speeds up to
30 m/min. are also feasible on modern portal type machining centers, depending on profile shape.
Rates of adhesive application
Please follow the adhesive manufacturer’s instructions. Apply the adhesive evenly and in sufficient quantities for beads of adhesive to be pressed out along the edges of the freshly glued edgebands, ensuring that the gaps between chips are filled. The amount of glue required depends on the density of the chipboard and the type of adhesive.
Bearing in mind the machine parameters, ensure that an adequate number of rollers are available and adjust the pressure to achieve the best possible appearance of the joint.
Thermoplastic edgebands require higher extraction power than duroplastic edgebands. The advantage of Doellken PVC Edge- bands is the lower static charge picked up when compared to other thermoplastic raw materials.
If possible, use cutters with 3 to 6 teeth, with ca. 70 mm diameter and at speeds between 12 000 and 18 000 rpm. Incorrect speeds or blunt cutters may damage the edgebands. In the event of smearing, reduce the speed of the cutter or cut against the feed (increase feed, if necessary).
Because PVC tends to fade after scraping, the plastic scrapings should not exceed 0.1 to 0.2 mm in thickness. To avoid chatter marks, the routers used for milling should be running true Diamond coated cutters are recommended. Hot air blowers may be useful to optimize scraping, particularly where color quality is critical.
Doellken PVC Edgebands are easy to buff on their radii using a buffing wheel. Any fading after scraping may simply be buffed away with these wheels, with the color of the radius then matching that of the edgeband itself. With through-feed edgeband gluing machines, remnants of the glue may also be removed with the buffing wheel. Glue remnants may also be removed using electronically controlled separating agent spraying units as is common in industry. This improves the scraper blade finish as well.