Epoxy Resin 128 — the liquid bisphenol A epoxy resin with CAS number 25068-38-6 — is the workhorse of the GCC coatings, flooring, adhesive, and construction chemical industries. Whether you are formulating a high-build epoxy floor coating for a Saudi warehouse, an anti-corrosion primer for offshore steel, or a structural adhesive for UAE construction projects, Epoxy Resin 128 is almost certainly your starting point.
This guide covers everything a GCC procurement manager or formulation chemist needs to know: what the technical specifications actually mean, how to select the right grade, how to pair it with the correct hardener, and what to look for when sourcing from a UAE or Saudi Arabia-based supplier.
What Is Epoxy Resin 128?
Epoxy Resin 128 is a liquid, unfilled, bisphenol A diglycidyl ether (BADGE) epoxy resin. It is produced by the condensation reaction of bisphenol A with epichlorohydrin in the presence of sodium hydroxide. The "128" designation refers to the product code widely used across Asian and Middle Eastern markets — it is equivalent to DER 331 (Olin), Epikote 828 (Hexion), and Araldite GY 250 (Huntsman) from Western manufacturers.
Key Technical Specifications
| Parameter | Typical Value | Why It Matters |
|---|---|---|
| CAS Number | 25068-38-6 | For customs, SDS, and regulatory compliance |
| Epoxy Equivalent Weight (EEW) | 182–192 g/eq | Determines hardener ratio — critical for full cure |
| Viscosity @ 25°C | 10,000–15,000 mPa·s | Affects application method and workability |
| Specific Gravity @ 25°C | 1.15–1.17 g/cm³ | For VOL/weight calculations in formulation |
| Colour (Gardner) | ≤ 2 | Light colour indicates good quality / low impurities |
| Hydrolysable Chlorine | ≤ 500 ppm | Low Cl = better electrical properties, less corrosion risk |
| Flash Point | > 200°C | Safe for transport, low fire hazard classification |
| Shelf Life | 24 months | At 15–35°C in sealed containers |
| HS Code | 3907.30 | For UAE and Saudi Arabia customs import documentation |
Grades of Epoxy Resin — Which Is Right for Your Application?
Not all "Epoxy Resin 128" from different manufacturers is identical. Key differentiators include:
- Hydrolysable chlorine content: Standard grade (≤500 ppm) is suitable for most industrial coatings and adhesives. Low-chlorine grade (≤200 ppm) is required for electrical applications and food-contact coatings.
- Colour consistency: For clear coatings and light-coloured topcoats, specify Gardner ≤1. For flooring and primers where colour matters less, ≤3 is acceptable.
- EEW consistency batch-to-batch: For precision hardener-to-resin ratios, tighter EEW specification (±3 g/eq) reduces cure variability. Ask your supplier for batch-to-batch COA data.
Applications in the GCC Market
Epoxy Resin 128 serves as the base resin in a wide range of industrial applications across the UAE and Saudi Arabia:
- Epoxy floor coatings — self-levelling, high-build, and mortar systems for industrial warehouses, car parks, and food processing facilities. Common in Saudi Arabia's expanding industrial cities (MODON).
- Protective coatings — anti-corrosion primers and intermediate coats for offshore structures, pipelines, and storage tanks. Critical in the GCC's petrochemical sector.
- Civil engineering grouts and adhesives — anchor adhesives, crack injection resins, and structural bonding in GCC infrastructure projects.
- Construction chemical raw material — used by construction chemical manufacturers to produce epoxy-modified cementitious systems and waterproofing membranes.
- Electrical potting and encapsulation — used with anhydride hardeners for transformers and switchgear.
Hardener Selection — The Most Critical Decision
Epoxy Resin 128 alone is inert — it only becomes a useful material when combined with a curing agent (hardener). The hardener choice determines open time, cure speed, final mechanical properties, chemical resistance, and yellowing resistance. The main hardener families used with Epoxy 128 in the GCC are:
| Hardener Type | Cure Speed | Best For | GCC Limitation |
|---|---|---|---|
| Polyamide (PA) | Slow (4-6h) | Adhesives, primers, maintenance coatings | Moisture-sensitive, can blush in high humidity |
| Poly(amido)amine (PADA) | Medium (2-4h) | Floor coatings, general purpose | Higher amine blush risk |
| Phenalkamine | Fast (1-2h) | Marine, tank lining, cold-weather application | Higher cost |
| Cycloaliphatic amine | Fast (1-3h) | UV-stable clear coatings, decorative | Low viscosity — requires careful mixing |
| Anhydride | Very slow (heat cure) | Electrical castings, high-temp applications | Requires oven cure, not for ambient use |
In the GCC climate — high ambient temperature and humidity in summer months — phenalkamine hardeners and moisture-tolerant amines are increasingly specified because they are less prone to the blushing and adhesion failures that affect standard polyamide systems. Read our guide on epoxy blushing →
Reactive Diluents — Reducing Viscosity Without Solvents
A common challenge with Epoxy Resin 128 in hot GCC climates is that even 30°C ambient temperature significantly lowers viscosity (workability improves), but in winter and in air-conditioned warehouses, viscosity increases substantially. Options for viscosity reduction:
- Benzyl alcohol — the most widely used reactive diluent for epoxy systems in the GCC. At 5-10% addition, reduces viscosity significantly without significantly affecting mechanical properties. Also acts as an accelerator and coalescent in cured films. Read our benzyl alcohol guide →
- Monoglycidyl ethers (C12-C14 AGE) — low-viscosity reactive diluents that reduce viscosity without sacrificing epoxy functionality. Slightly reduce Tg and chemical resistance at high loadings.
- Xylene / aromatic solvents — non-reactive, used in solvent-based systems. Increasingly restricted under GCC VOC regulations. Read our xylene guide →