What are Hot Melt Adhesives?
Hot melt adhesives are 100% solids bonding agents applied in the molten state that form bonds when cooling.
Hot melt adhesives are always comprised of:
- Polymers: These are the hot melt adhesive backbone and provide cohesive or internal strength. They dictate the level of performance of temperature considerations and toughness, durability and flexibility of the bond. Polyolefins are an example of a polymer and are used in EVA formulations.
- Natural or synthetic tackifying resins
- Plasticizers (mostly waxes and paraffin): These enable the adhesive to adapt to different open times and setting times.
- Elasticity: This is the adhesive’s ability to store energy and use that energy to retain original shape when moved.
- Viscosity: This is the adhesive’s resistance to flow.
- Modulus: This is the adhesive’s flexibility levels after it sets.
What are EVA Adhesive Benefits?
These adhesives offer the following benefits:
- Improved End of Life: EVAs offer compatibility with bio-based and renewable materials, which improves recyclability levels and end of life disposal.
- Reduced Environmental Impact: Formulated with non-hazardous materials, they comply with strict regulations, minimizing volatile organic compounds (VOCs) and overall harmful emissions. They also offer a long shelf life and decreased adhesive consumption compared to other technologies, which reduces waste.
- Enhanced workability: They are low odor and can be easily sprayed, improving working conditions.
- Streamlined operational efficiencies: These adhesives don’t require stop-start operations, are fast setting and require little maintenance, which increases efficiencies and improves lean manufacturing.
- Enhanced design possibilities: EVAs can bond to multiple substrates, which increases design options.
- Increased safety: As a moisture-free bonding option, they reduce bacteria and virus contamination, allowing them to be able to be food grade and compatible with pharma white rooms.
What are the main applications for EVAs?
EVAs are multi-purpose, offer fast setting time, hot and cold temperature resistance, food safety compliance and compatibility with difficult substrates. Additionally, they improve efficiency and speed-up production by forming a bond quickly without needing time to cure or dry. As a result, they work well for: