Hot melt adhesives

Hot melt adhesive is one of the types of glue that is most used in the woodworking industry. This glue has a solid form at room temperature, and it needs to be heated in its application. In the hot condition, it will melt and form a liquid, then it can be coated at the surface. Two-faced application is needed, and then after the 2 pieces are unified, he will cool and harden to form a strong bond. Hot-melt adhesive is mainly used in specialty applications, mainly due to its ability to form bonds quickly. It is most used in the furniture and cabinetry assembly, window construction, and edge banding of panels or decorative laminates. Rapid bond formation is the advantage of this glue. It is preferred in the manufacturing operations because minimal clamping time is needed. The hot melt adhesive is very practical and easy to use with the strong and thermosetting adhesion result. No thinner or solvent that will thin the glue and reduce the strength of the glue mixture. Neither the water that will affect the moisture contents the interface. The disadvantage of this glue is its high price and the fact that the glue in some conditions cannot perfectly wet the surface, as well as the glue that uses solvents.

There are several types of hot melt adhesive, but according to their formulation, they can be grouped into ethylene vinyl acetate and polyamide. This ethylene vinyl acetate is made by gas-phase polymerization to yield non-solvated polymers. It has a wide range of properties according to the ratio of the vinyl acetate polymer and the molecular weight of the polymer. It is relatively inexpensive, but some time it has problems with creep as the temperature increases. Since they contain large amounts of lower molecular weight in the adhesive formulations and there is limited attraction between the polymer chains,. It is used more with paper products than with wood products.

Polyamide hot-melt adhesives have stronger bonds with better creep resistance. Its strong hydrogen bonds between the chains make it have better creep and heat resistance. It is quite expensive because it is more used to the high-value products that need more durable bonds. It is most used in furniture assembly, window or door construction, and edge banding.

Hot melt adhesives need the heating machine in the application process. The tool consists of a container for glue, which is equipped with a heater, hose, and gun to apply the hot glue to the desired surface. The temperature needed could vary depending on the type of glue used, but usually the glue will start melting at temperatures around 80 C, but usually it needs to be heated at temperatures about 150 to 200 Celsius to achieve low viscosity in the application. And since the glue will harden and set when it is cold, the machine needs to keep hot when it contains the glue. The glue should be released from the machine, and the equipment should be cleaned when it is stopped operating. To clean the hose and lines, set the temperature to between 80 and 100 degrees Celsius, where the glue begins to melt, drain the glue, and then use glue thinner. Make sure there is no glue left in the machine, line, and gun before leaving the machine, since the rest of the glue in the machine will harden and clog the line.