Solvent-based adhesives have historically been in widespread use in production lines. These adhesives are typically hard polymers that are dissolved and softened with a solvent. As this solvent evaporates, the adhesive re-hardens and forms a strong bond.
Today, however, many manufacturers have moved on to the use of thermoplastic hot melt adhesives – let’s take a look at how these stack up against solvent-based adhesives, and whether they are truly deserving of the extensive praise they receive.
Speed of Application
There’s little quicker than a melt adhesive – they melt almost immediately under high temperatures, and can form a solid bond in just seconds after application. This is crucial in keeping a production line moving and limiting the amount of equipment needed (no dedicated drying platform or machinery.) The number of formulas available make any application possible. Whether you need a long or short open time or a permanent or temporary bond there is a glue formula for you.
Since solvent-based adhesives require the solvent to fully evaporate before reaching effective strength, they will require not only additional time to dry, but also a means to keep the two surfaces clamped together during this period.
Solvent-based adhesives are chemical mixtures with a marked effective shelf life – and one that rapidly accelerates upon first opening the container. It can be challenging to keep their use economical, as it requires highly accurate predictions about the quantities that will be used within a short time frame. Hot melt adhesives are much more stable, and can last extremely long times if kept under proper temperature conditions.
Storage and Disposal
Melt adhesives are straightforward and non-toxic polymers that achieve bonds by melting under heat and re-solidifying. They’re quite simple to store, requiring no special conditions other than the avoidance of extreme temperatures.
Solvents, by contrast, can contain toxic chemicals that are not easily stored or disposed of. Once they reach the end of their effective shelf life, they cannot simply be tossed into the garbage or poured down a drain – this can pollute lakes, streams, and groundwater. Even releasing fumes during the drying process can be a health and environmental hazard – as such, they must be sealed at all times when not in use.
Hot melt adhesives are the clear-cut winner over their solvent-based counterparts. For more information on hot melt glue dispensing equipment, or to place a purchase order, contact Sure Tack Systems today.