11.7 ADHESIVES, CLEANERS, CHEMICALS hot melt adhesives and accessories for edge banders Hot melt adhesives – basic information Choice of adhesive Each of the parameters listed in the hot melt adhesive overview is an important consideration when choosing the right adhesive. PUR – POLYURETHANE: is designed for a fixed, durable but above all water-resistant joint. It is the right solution for kitchen or bathroom furniture. PUR is a chemically reactive adhesive and curing takes place not only by physical curing, but also by chemical reaction with the moisture of the particle board and the humidity of the air. It is therefore recommended to process this type of adhesive at ambient temperatures between 18 and 35°C and ambient humidity of 30–60%. A very beneficial and recommended means of making the bonded joint easier and faster to cure is to spray Riepe cooling compound LP289 on the top and bottom edge of the furniture components. We have experience with the additional mounting of this spray even on older edge banders. EVA – ETHYLENE-VINYL ACETATE: is a thermoplastic based adhesive unlike PUR – when the adhesive is heated, a thermal reaction takes place and the EVA material can be re-melted. This also makes a difference when cleaning the tools and components of the edge banders. While EVA residues are easier to remove, special products are recommended for cleaning PUR residues. Selection according to filler content EVA-based hot melt adhesives give us the choice between pure resin material or resin supplemented with a mineral filler such as chalk. The difference can be seen in the table. Unfilled hot melt adhesives require a faster workpiece feed and create a smaller gap due to the need for a thinner application. In contrast, filled hot melt adhesives offer us a simpler process and prevent the formation of adhesive stringing. Even in the case of filled adhesives, we can achieve the optimum width of the bonded joint. For both types of hot melt adhesives, the already mentioned cooling spray LP 289 from Riepe is a great helper, which also has an antistatic effect. Spraying immediately after taping reduces the risk of contaminants entering the joint, especially for filled adhesives. Every leakage between the edge bander and the board can be a potential source of joint instability in the future. Riepe NFLY protective spray can be applied directly to the edge bander with one nozzle to improve slip resist- ance and prevent tool deposits. The coating thus formed will reach the cutters and the blades from the edge, which reduces the rate of their wear. Selection by feed rate Each of the adhesive parameters must be seen in the context of the other parameters. The machinery producer determines what feed rates we are able to implement. Industrial edge banders, which achieve feed speeds of 40 or even 100 m/min., behave differently than manual edge banding machines. The higher the speeds, the more consideration needs to be given to the formation of residual fibre from hot melt adhesives and the amount of adhesive deposition. We offer a wide range of hot melt adhesives along with a supporting assortment of auxiliary products from the producer Riepe. How to choose the right chemical?
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