In industrial use, hot melt adhesives (HMAs) provide several advantages over solvent-based adhesives.
- Volatile organic compounds that are reduced or eliminated
- The drying or curing step is eliminated
- Hot melt adhesives have long shelf life and usually can be disposed of without special precautions
- HMAs do not lose thickness during solidifying; solvent-based adhesives may lose up to 50-70% of layer thickness during drying
Some challenges of HMAs include:
- Thermal load of the substrate, limiting use to substrates not sensitive to higher temperatures
- Loss of bond strength at higher temperatures, up to complete melting of the adhesive.
- Some HMAs may not be resistant to chemical attacks and weathering
The above challenges can be reduced however, by using a reactive adhesive that after solidifying undergoes further curing e.g., by moisture (e.g., reactive urethanes and silicones), or is cured by ultraviolet radiation.
Popular applications for hot melt adhesives include, but are not limited to:
- Closing the flaps of corrugated boxes and paperboard cartons in the packaging industry
- Spine gluing in the bookbinding industry
- Profile-wrapping, product assembly and laminating applications in the woodworking industry
- Disposable diapers are constructed through the use of HMA, bonding the non-woven material to both the backsheet and the elastics
- Many electronic device manufacturers may also use an HMA to affix parts and wires. or to secure, insulate, and protect the device’s components
It’s worth noting that mass-consumption disposable products such as diapers necessitate development of biodegradable HMAs. “Going Green” is important in any supply chain, and that includes your adhesives.
Do you have a hot melt application that requires specific bonding properties for your application, including environmentally-friendly outcomes? Contact us for more information.