Hot melt adhesives are also known as hot glue adhesives, they consist of thermoplastic polymers that are melted and then applied as a liquid, but when they cool down, they become dry and solidify. Hot melt adhesives are used in both commercial and residential areas. Hot melt adhesives in India are generally based on thermoplastic polymers, which are complete solid based formulations. They are solid at room temperature and they are activated when they are heated above their softening point, at which stage they are liquid, and hence can be processed. After they are applied on substrates, they retain the ability to wet the substrate until they solidify. Once they are solidified, they return to a physical state that has structural integrity and can be used as an adhesive. Hot melt adhesives in India are mostly applied by rolling, extruding and spraying, joining is carried out immediately after application or after reheating the solidified layer.
Hot melt adhesives in India are used for a variety of purposes such as crafts, hobbies, woodworking, assembly, packaging, labeling and taping, upholstery, book binding, manufacturing of hygiene and sanitary products and different types of industrial assembly, etc.
Prior to 1940 water based adhesives were used globally but since they would loose their adhesion in humid climate, scientists were constantly working on an alternative to water based adhesives. Hot melt adhesive or hot glue was invented by Paul Cope around 1940; since then, hot melt adhesives rapidly replaced water based adhesives on a global level. Hot melt adhesives were a better option because they were cost effective, easy to use, easy to store, possessed excellent sealing quality, long life, appeared clean, suitable for all weathers and their formulas were made for a variety of applications and materials. There are many different types of hot melt adhesives used globally, but hot melt adhesives in India mainly consist of four types, namely: Ethelyne vinyle actetate(EVA), polyamide (PA), polypropylene(PP) and polyurethane(PU).