Frequently Asked Questions
Reactive Diluent Types — How to Choose
Reactive diluents are mono- or multi-functional glycidyl ethers that co-react with the epoxy system during cure. Unlike inert solvents, they become part of the cured network, contributing to crosslink density and film properties.
| Type | CAS | EEW (g/eq) | Viscosity (mPas) | Effect on Film |
|---|---|---|---|---|
| RD12 (C12-C14 AGE) | 68609-97-2 | 285–310 | 5–15 | Good flexibility, slight softening |
| BGE (Butyl glycidyl ether) | 2426-08-6 | 130–145 | 2–5 | Significant softening, lower viscosity |
| BDGE (Butanediol DGE) | 2425-79-8 | 110–130 | 15–25 | Bifunctional — maintains crosslink density |
| Benzyl alcohol | 100-51-6 | N/A (non-reactive) | 5–6 | Acts as plasticiser / flexibiliser |
Loading Calculation & EEW Impact
When adding RD12 to an epoxy formulation, the effective EEW of the blend changes. This must be accounted for when calculating hardener stoichiometry:
Example: Blend EEW Calculation
Epoxy resin YR-128 (EEW 185) + 15% RD12 (EEW 295)
Blend EEW = 100 / [(85/185) + (15/295)] = 202 g/eq
Use this blend EEW when calculating the polyamide or amine hardener dosage (PHR = Amine AHEW × 100 / blend EEW).
Typical loading of RD12 is 5–20 phr (parts per hundred resin). Higher loadings reduce viscosity and Tg but increase flexibility. For floor coatings requiring hardness, keep RD12 below 10 phr. For flexible adhesives, up to 20 phr is acceptable.
Skin Sensitisation — Handling Note
C12-C14 alkyl glycidyl ethers (RD12) are classified as skin sensitisers (H317) under GHS/CLP. Workers handling RD12 must wear nitrile gloves and eye protection. Repeated skin contact without PPE can lead to sensitisation reactions. Always refer to the SDS for full handling requirements.