From viscosity reduction and wetting to heat-resistance improvement — a detailed look at the multiple roles of FT wax in EVA hot-melt adhesive; grade parameters from the real Heyee Chem HY series.
Hot-Melt Adhesive (HMA, most commonly EVA-based) needs suitable melt viscosity at application temperature for coating, then rapid solidification after cooling to form a strong bond. Low-molecular-weight polyolefin wax contributes:
FT wax, with narrow MWD, high purity, white color and low odor, has clear advantages in hygiene, packaging and bookbinding where consistency and low odor are required.
| Grade | Congeal / Drop point | Penetration | Form | Use |
|---|---|---|---|---|
| HY-102 | congeal 99–103°C / mp >110°C | <2 | white powder | general EVA HMA |
| HY-W104 | congeal 102–108°C / mp ≥117°C | ≤1 | white powder | heat-resistant / high-softening HMA |
| HY-105 | congeal >95°C / mp >105°C | <9 | bead | heat-resistant HMA |
| HY-40 | softening ≥116°C / 149°C visc 20–40 cP | – | white bead | melt-flow regulator |
| HY-720 (liquid) | – / flash >300°C | – | liquid | further viscosity cut / processing aid |
general EVA HMA → HY-102, HY-7100D
heat-resistant HMA / high softening point → HY-W104, HY-105
regulate melt flow → HY-40 (149°C viscosity 20–40 cP)
further viscosity cut / liquid aid → HY-720 liquid wax
HMA (commonly EVA-based) needs suitable melt viscosity at application temperature for coating, then rapid solidification after cooling for a strong bond. FT wax, with low melting point and high viscosity-regulation efficiency, significantly lowers melt viscosity, improves wetting, shortens open time and speeds curing; high-drop-point grades (e.g., Heyee HY-W104, drop point ≥117°C) also raise the adhesive's heat resistance and softening point.
Low-drop-point wax lowers system melt viscosity and speeds spreading, usually shortening open time (open time = the tacky window after coating during which bonding is possible); high-drop-point wax raises overall heat resistance and softening point. By blending low/high drop-point waxes, formulation balances viscosity, open time and heat resistance. Heyee HY-40 (149°C viscosity 20–40 cP) is used to regulate melt flow.
General EVA HMA: HY-102 (congeal 99–103°C, drop point >110°C, penetration at 105°C); melt-flow regulation: HY-40 (149°C viscosity 20–40 cP); when lower viscosity or a processing aid is needed, consider HY-720 liquid wax (congeal 20 cP, flash point >300°C).
Appropriate wax mainly improves processability (viscosity cut, wetting, curing) with limited effect on bond strength; but excess dilutes the main resin, lowers cohesion and causes brittleness or easy peeling. Determine the upper limit by trial — typically the shortest open time that achieves good coating and curing — and verify peel strength.
FT wax has narrower MWD, higher purity, whiter color and lower odor, with better process stability and appearance than ordinary paraffin; its cost is more controllable than microcrystalline wax. For premium packaging, hygiene and bookbinding demanding low odor and high consistency, FT wax (HY-W104, HY-102) is preferred.
