Concept:Hot-melt adhesives are solvent-free thermoplastic polymer systems that melt to a low-viscosity liquid upon heating and solidify rapidly upon cooling to ambient temperature.
Formula / Reaction:$$\text{Polymer (Solid)} \xrightarrow{+\Delta H} \text{Polymer (Melt)} \xrightarrow{\text{Apply / Cool}} \text{Polymer (Solid Bond)}$$
Solution:- Common hot-melt adhesives include ethylene-vinyl acetate (EVA), polyamides, and polyolefins.
- They form physical bonds without chemical curing or solvent evaporation, enabling high-speed manufacturing lines.
Why other options are incorrect:- Contact adhesives: Polychloroprene solutions that set through solvent evaporation and contact coalescence.
- Cyanoacrylates: Reactive liquid monomers that cure via moisture-initiated anionic polymerization.
- Two-part epoxies: Chemically reactive systems that cure via step-growth polyaddition.
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