Adhesives/
Hot Melt Adhesives
Defined by the curing process that adheres it to objects and also bonds objects to other objects, hot melt adhesives are made up of thermoplastic resins. They are in the same adhesive family as silicone, epoxy and acrylic adhesives. Hot melt adhesives are also considered pressure sensitive adhesives, or PSAs. It is when they are molded into the tacky glue gun form and require pressure plus heat to be applied that the term PSA is also valid. The hot melt vehicle, the hot glue gun, is usually made of plastic with metal attachments, such as a small kickstand underneath the head of the gun to support it when it is set down while still hot. A heating mechanism inside the gun can be powered by an electrical cord, batteries or even butane gas, depending on the context. There are high temperature guns used for metal, plastic and ceramic bonding in domestic and industrial settings, as well as low temperature models that are commonly employed in at home crafting contexts with delicate objects such as paper.
Hot melt adhesives are used in many industries. Most commonly this type of adhesive is used for packaging, textiles, labels, stamps, envelopes and product assembly processes. Hot melt adhesives may also be used in home construction, aircraft and aerospace assemblies and automotive assembly. These adhesives have some limitations. Hot melts cannot be used with heat sensitive components because their adhesive bonds lose strength at high temperatures, which can cause the adhesive to melt. Another downside is that chemical resistance may be lacking with many types of hot melt adhesives. However, depending on the application, the upsides of using hot melt adhesives are numerous too. Because of the demand to reduce or eliminate volatile organic compound (VOC) emissions from adhesive applications, hot melt adhesive use is expected to increase during the future. Hot melt adhesives do not contain the solvents that may be emitted by other types of adhesive. Significant cost-savings may also be achieved by implementing hot melt adhesives instead of solvent-based systems.
