1. Product Overview
LOCTITE® HHD 3618BK is a black, odorless, one-part polyurethane hot melt adhesive that cures through moisture. It is reactive and pressure-sensitive, providing high initial strength immediately after joining. Designed for manual or automated assembly lines, it offers excellent adhesion, good impact resistance, fast cure, and reworkability. Full cure is achieved within 1–5 days depending on humidity and substrate conditions, while handling strength is immediate.
2. Applications
Substrate pretreatment recommendations: Surfaces must be clean, dry, and free of oil or grease; maintain substrate temperature above 20°C; preheating may be applied.
Application methods: Heating cartridge guns or syringe-type melting equipment; reduce application temperature during longer rest periods to prevent viscosity increase.
3. Typical Properties
| Property |
Value |
| Uncured Material |
|
| Technology |
Polyurethane Hot Melt |
| Appearance |
Black solid |
| Odor |
Odorless |
| Components |
One-part, no mixing required |
| Solids Content, % |
100 |
| Density @ 25°C, g/cm³ |
1.1 |
| Viscosity @ 110°C, mPa·s |
7,500 |
| Curing Performance |
|
| Open Time @ 25°C, min |
>4 |
| Preheating Schedule @ 110°C, min |
20–30 |
| Application Temperature, °C |
100–130 |
| Cure Method |
Moisture |
| Full Cure Time |
1–5 days (depending on humidity and substrate conditions) |
| Cured Material |
|
| Elongation, % |
854 |
| Modulus, N/mm² |
77 |
| Tensile Strength, N/mm² |
14.55 |
| Adhesion (PCGF to Ink Glass, 24h), N/mm² |
>8 |
LOCTITE® HHD 3618BK exhibits immediate handling strength after bonding, with curing rate influenced by environmental humidity, substrate moisture, permeability, and adhesive layer thickness. Optimal storage is 8–28°C in unopened containers.