1. Introduction
A food grade epoxy system is a specially designed two-pack epoxy coating
or lining system used for food-processing areas, potable-water tanks, storage vessels,
pipelines, dairy plants, food floors and hygienic washable surfaces.
Important: Ordinary epoxy paint should not be called food grade unless
the complete system is tested and certified for the exact food-contact or potable-water application.
2. Recommended Chemistry
Part A — Epoxy Base
- Liquid epoxy resin
- Bisphenol-A / Bisphenol-F epoxy
- High-solids or solvent-free grade preferred
- Food-contact acceptable pigments
- Inert fillers
- Wetting, flow and defoaming additives
Part B — Hardener
- Modified amine hardener
- Cycloaliphatic amine
- Phenalkamine hardener
- Low-odour curing system
- Low extractable and low leachable type
3. Typical Applications
| Application |
Recommended System |
Technical Requirement |
| Food factory floor |
Epoxy primer + epoxy screed / mortar + food-grade epoxy topcoat |
Smooth, washable, chemical-resistant, non-dusting surface |
| Potable-water tank |
Certified solvent-free epoxy lining |
No taste, no odour, no harmful leaching |
| Food storage tank |
High-build epoxy lining |
Full cure, low extractables, food-contact compliance |
| Dairy / beverage plant |
Hygienic epoxy floor and wall coating |
Resistance to cleaning chemicals and hot water |
4. Typical White Food Grade Epoxy Formulation Concept
Part A — Epoxy Base
| Raw Material |
Approx. % |
Function |
| Liquid epoxy resin, EEW 180–190 |
35–45 |
Main binder |
| Reactive diluent, if permitted |
2–5 |
Viscosity reduction |
| Titanium dioxide |
15–25 |
Whiteness and opacity |
| Barytes / silica / inert filler |
15–25 |
Body, hardness and cost balance |
| Wetting and dispersing additive |
0.5–1.5 |
Pigment wetting |
| Defoamer |
0.2–0.5 |
Air release |
| Flow additive |
0.2–0.5 |
Surface smoothness |
| Anti-settling additive |
0.5–1.0 |
Storage stability |
| Solvent, only if allowed |
0–5 |
Viscosity control |
Part B — Hardener
| Raw Material |
Approx. % |
Function |
| Modified amine / cycloaliphatic amine / phenalkamine |
80–100 |
Curing agent |
| Approved flexibilizer / accelerator, if required |
0–10 |
Cure control and flexibility |
| Solvent, only if permitted |
0–10 |
Application viscosity |
Mix ratio: The final Part A : Part B ratio must be calculated based on
epoxy equivalent weight and amine hydrogen equivalent weight. It should not be fixed by guesswork.
5. Technical Requirements
Performance
- Excellent adhesion
- Good hardness
- High chemical resistance
- Resistance to detergent and sanitizer
- Good hot-water resistance
Food Safety
- No tainting of food
- No taste transfer
- No odour after curing
- Low migration
- Low extractables
Surface Quality
- Smooth finish
- Non-porous surface
- Easy cleaning
- No cracking
- No blistering
6. Surface Preparation and Application
| Step |
Recommended Practice |
| Steel surface preparation |
Abrasive blast cleaning to Sa 2.5 standard |
| Surface profile |
50–75 microns for tank lining |
| Concrete surface |
Dry, clean, laitance-free and mechanically prepared |
| Moisture |
Concrete moisture must be within acceptable limit before coating |
| Application |
Brush, roller, spray or airless spray depending on system |
| Recommended DFT |
200–300 microns for floor topcoat; 400–600 microns for tank lining |
| Curing |
Minimum 7 days at 25–30°C before food or water contact, unless otherwise certified |
7. Testing and Validation
- Migration / extraction test
- Odour and taste transfer test
- Potable-water contact test, if used for water tanks
- Adhesion test
- Pencil hardness test
- Chemical resistance test
- Hot-water resistance test
- Detergent and sanitizer resistance test
- Holiday test for tank lining
- Heavy metal test for pigments and fillers
8. Compliance Caution
The term food grade should be used only when the full coating system,
including resin, hardener, pigments, fillers, additives, application method and curing condition,
has been properly tested and documented.
For food-contact tanks, potable-water tanks, edible-oil storage, dairy vessels and beverage
processing areas, use only a certified epoxy system with proper food-contact or potable-water
approval.
9. SaitechLabs Recommendation
For industrial customers, SaitechLabs recommends developing food-grade epoxy systems as a
documented technical dossier containing formulation, raw material validation, SOP, quality
control standards, application procedure, curing protocol, testing plan, TDS, MSDS and
compliance documentation.
Best practice: Do not depend only on formulation. Build a complete system
around raw material selection, processing discipline, surface preparation, testing, curing
and certification.
