Edge sealing hot melt adhesive is a kind of adhesive specially used for edge sealing of artificial sheet. It is a solvent-free thermoplastic adhesive. When the hot melt adhesive is heated to a certain temperature, it changes from solid to molten state. When the coating is applied to the wood-based panel substrate or the surface of edge sealing material, it is cooled to solid state, and the edge sealing material is bonded together with the base material.
1, edge sealing hot melt adhesive base material
(1)EVA (ethylene – vinyl acetate copolymer resin) base material hot melt adhesive, this hot melt adhesive can be divided into two types of packing and no packing. EVA as the base material is a common edge sealing hot melt adhesive production technology, its main limitation is poor heat resistance. The operating environment temperature of the panel furniture sealed with EVA hot-melt adhesive shall not be higher than 120°C;
(2)POL YAMIDE(polyamide) base hot melt adhesive. This hot melt adhesive is characterized by excellent heat resistance and fast curing, and its main disadvantage is its high price.
(3)HMPU(polyurethane) base material hot melt adhesive, which is a kind of hot melt adhesive with good performance, is the guarantee of high quality plate edge sealing. It is expensive and requires special methods of use.
2. Viscosity of edge sealing hot melt adhesive
The viscosity of edge sealing hot melt adhesive cannot directly reflect the performance of the adhesive. In general, edge sealing hot melt adhesive viscosity is higher, its initial adhesive strength is better, but the coating performance is worse. Low viscosity hot melt adhesive coating amount is small, wettability can be better. Some hot melt adhesives with low viscosity and fast curing speed may also have high initial adhesive strength. For particleboard with poor quality, hot-melt adhesive with high viscosity should be selected for edge sealing. This is because hot-melt adhesive with high viscosity has poor fluidity and is not as easy to enter into the pore of the edge of particleboard as hot-melt adhesive with low viscosity, so that hot-melt adhesive can be fully coated on the edge of the board.
3, edge sealing hot melt adhesive density
The density of edge sealing hot melt adhesive is generally 0.95-1.6g/cm 3, and its density depends on the number of packing (the more packing, the greater the density). Due to the sheet edge sealing requirements to reach a certain area of glue, so the density of the fillerless hot-melt adhesive per unit length of glue is less than that of the fillerless hot-melt adhesive. And because the filler less hot melt adhesive bonding performance is better, to achieve the same sealing effect, the use of filler less than the filler hot melt adhesive is possible. In order to reduce the amount of coating, the edge sealer must have a good coating system.
4. Softening point and service temperature of edge sealing hot melt adhesive
The softening point is the index of heat resistance of edge sealing hot melt adhesive. The higher the softening point is, the less easy the edge sealing hot melt adhesive will melt. At the same time, the softening point is also an important aspect to measure the temperature resistance of board furniture. In Europe, there has been a set of testing methods for the heat resistance of plate sealing edge, and a standard has been put forward for the heat resistance of plate furniture. Countries such as France, Germany and Italy already did not produce the sealing edge hot melt glue of low softening point on a large scale, but domestic manufacturer (include Taiwan manufacturer) still produce and offer domestic market, the reason is domestic furniture manufacturer and consumer are opposite at present board type furniture, especially the heat-resisting performance of kitchen furniture does not take seriously enough. The softening point range of EVA hot melt adhesive is generally between 90-135℃.
The use temperature of hot melt adhesive refers to the temperature of glue on the rubber roller of the sealing machine. Only at this temperature, hot melt adhesive can achieve good adhesive strength. The temperature displayed on some banding machines is quite different from the actual temperature, so it is necessary to check the temperature of the machine regularly. If the temperature of edge sealing machine is too high, the glue will be carbonized and smoke. Too low, and will make the adhesive strength decline.
5. Opening time of edge sealing hot melt adhesive and feeding speed of edge sealing machine
The opening time of edge sealing hot melt adhesive refers to a period of time before the edge sealing machine starts from gluing to pressing the edge sealing tape to the base material. The opening time varies with different types of adhesive. The feeding speed and opening time of edge sealing machine are closely related, both of which are very important in the selection and use of hot melt adhesive. Fast feeding edge sealing machine must choose hot melt adhesive with short opening time, otherwise, choose hot melt adhesive with long opening time.
For most manual edging machines, the opening time of the hot melt adhesive is required to be long enough to seal the bending parts due to manual operation of the worker. Hot melt adhesive is generally coated in the sealing tape, in order to ensure the quality of sealing, domestic manual sealing machine has also used double-sided adhesive coating method. The glue tank temperature of manual edge sealer is generally controlled below 180°C (BRANDT manual edge sealer can be heated to more than 200°C), so hot melt adhesive with temperature below 180°C is used. If the thin PVC edge sealer is sealed with a thickness of less than 0.2mm on the manual edge sealer, the use temperature of the hot melt adhesive must be about 120°C
Post time: Sep-28-2020