Hot melt coating sprays molten wax or lipid films (typically melting at 50–85 ℃) that solidify on the pellet, granule or tablet under cooling air — no solvent, no VOC handling, no drying step. One dense film delivers moisture protection, taste masking, controlled release and API isolation.
When hot melt beats water-based coating
- The API is moisture-sensitive — the process never introduces water.
- The facility has no solvent recovery or explosion-protected zones — no VOC compliance burden.
- You need to cut batch time — droplets solidify on cooling, so there is no drying phase.
- Dense films for taste masking — molten films are less porous than aqueous ones.
The real process barrier: the gun clogs
- Molten material solidifies the moment it leaves the heat zone — a standard spray gun will block.
- The dedicated system is a trio: heated tank + heat-traced tubing + thermostatically heated gun, kept above melting point end to end with an anti-solidification tip.
What equipment you need
- Already own a fluid bed or coater: a retrofit kit (heated gun, tubing, temperature control) — main machine untouched.
- New line: turnkey tiers pairing the process with a 30 g mini bed, a pilot bed, or a DPL-120 production bed.
FAQ
Is hot melt coating suitable for controlled-release pellets?
Yes — wax and polymer blends tune release kinetics by film thickness and composition; the dense film also delivers moisture protection and taste masking in the same step.
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