What Is Cardolite NC-562?
Cardolite NC-562 is a cardanol-based epoxy hardener manufactured by Cardolite Corporation (USA). The active base is a reaction product of cashew nut shell liquid (CNSL) with polyamines. The phenolic ring of cardanol with its long C15 aliphatic side chain gives the cured film unique properties:
- Moisture tolerance: cures on damp and wet substrates
- Flexibility: higher elongation at break vs. rigid amines
- Chemical resistance: excellent resistance to petroleum products, salt solutions and dilute acids
- Low-temperature curing: active from +5°C
Technical Properties
| Property | Cardolite NC-562 | KH-816 (comparison) |
|---|---|---|
| Type | Cardanol amine adduct | Polyamidoamine adduct |
| AHEW (active hydrogen equiv. weight) | ~105–115 | ~95–105 |
| Viscosity at 25°C, mPa·s | 500–2000 | 300–800 |
| Dosage with KER 828 (phr) | 20–30 | 25–30 |
| Pot life (200 g, 25°C) | 2–4 hours | 30–60 min |
| Touch dry at 20°C | 8–12 hours | 4–6 hours |
| Full cure at 20°C | 7 days | 5–7 days |
| Min. application temperature | +5°C | +10°C |
| Application on wet surfaces | Yes | No |
How Moisture Tolerance Works
Standard amine hardeners (KH-816, DETA, TETA) react with moisture and CO₂ to form carbamates — a waxy white "amine blush" on the film surface. On wet concrete, water prevents proper wetting and adhesion.
Cardolite NC-562 contains aromatic amines with a hydrophobic C15 side chain that:
- Displaces water from the substrate surface (hydrophobic displacement effect)
- Slows carbamatisation — surface blush is minimal
- Allows the hardener to diffuse through a thin moisture layer to reach the substrate
Applications
Marine and Hydraulic Structures
Protection of steel piles, bridge piers and caissons. Suitable for application in tidal zones and under constant water spray. Adhesion to steel is maintained after re-immersion.
Concrete Floor Repair
After high-pressure washing, concrete does not need to dry fully. Primer based on KER 828 + NC-562 can be applied at surface moisture up to 8–10%.
Underground Structures and Tunnels
Waterproofing of tunnel walls, basements and mine shafts where humidity > 90% RH is the norm. NC-562 provides reliable adhesion where standard systems delaminate within 1–2 seasons.
Petroleum and Water Tanks
Internal lining for diesel, crude oil and process water tanks. Resistance to hydrocarbons and salt water.
Winter Construction
At +5…+10°C, standard systems do not cure or cure extremely slowly. NC-562 enables anti-corrosion work during autumn and spring without substrate heating.
Formulations with Cardolite NC-562
Steel Primer (Wet Conditions)
| Component | Mass, g | Role |
|---|---|---|
| KER 828 | 100 | Epoxy matrix |
| Cardolite NC-562 | 25 | Hardener |
| Zinc dust | 120 | Cathodic protection |
| Talc | 20 | Rheology |
| Solvent (xylene) | 10–20 | Viscosity reduction |
Comparison: NC-562 vs KH-816 in Difficult Conditions
| Condition | KH-816 | Cardolite NC-562 |
|---|---|---|
| Temperature +5°C | Does not cure | Cures |
| Damp concrete surface | Delamination | Strong adhesion |
| Marine atmosphere | Acceptable | Preferred |
| Amine blush | Pronounced | Minimal |
| Pot life | 30–60 min | 2–4 hours |
| Film hardness | High | Moderate |
| Cost | Lower | Higher |
