This water-based intumescent paint formulation for interior structural steel uses 22% LH360 VAE emulsion. The tables list all 17 ingredients in the order they are added. The mixing procedure is divided into three stages for trial batches.
Reference formulation for a water-based intumescent steel coating
All ingredient proportions total 100%. The tables follow the three stages of addition described in the preparation instructions below.
Stage 1: Water and additives
| Ingredient | Proportion (%) | Supplier |
|---|---|---|
| Water | 20 | — |
| Propylene glycol | 2 | — |
| AP-95 | 0.15 | XYZCHEM |
| Wetting and dispersing agent 104E | 1 | XYZCHEM |
| Defoamer B199 | 0.3 | XYZCHEM |
Stage 2: APP-83C, powders and XY510
| Ingredient | Proportion (%) | Supplier |
|---|---|---|
| APP-83C | 22 | XYZCHEM |
| Melamine | 10 | — |
| Pentaerythritol | 10 | — |
| Aluminium hydroxide | 4 | — |
| Titanium dioxide | 7 | — |
| XY510 | 0.15 | XYZCHEM |
Stage 3: LH360 and remaining ingredients
| Ingredient | Proportion (%) | Supplier |
|---|---|---|
| LH360 | 22 | XYZCHEM |
| Defoamer 680 | 0.1 | XYZCHEM |
| Thickener 530 | 0.1 | QingHai Trading |
| CMC | 0.15 | QingHai Trading |
| ZOE-T | 0.3 | QingHai Trading |
| Water | 0.75 | — |
Water is added in two stages: 20% in the first stage and 0.75% in the third. A dash indicates that no supplier is listed.
Coating preparation and mixing sequence
Add the ingredients one by one in the order shown in the tables, adjusting the mixing speed at each stage:
- Stage 1: Maintain 400–500 rpm and add the stage 1 ingredients in sequence while mixing.
- Stage 2: Adjust to 800 rpm and add the stage 2 ingredients in sequence while mixing. After adding XY510, increase the speed to 1,500 rpm and mix for 20 minutes.
- Stage 3: Adjust to 800 rpm and add LH360 and the remaining stage 3 ingredients in sequence while mixing.
LH360 VAE binder properties and selection
The LH360 VAE binder used in this formulation is a water-based vinyl acetate-ethylene copolymer emulsion for intumescent coatings.
LH360 offers good compatibility with pigments and fillers, good electrolyte stability and excellent pigment binding. It contains no solvents, plasticizers or alkylphenol ethoxylates (APEO), and has very low VOC content.
| Property | Product data |
|---|---|
| Appearance | Milky white liquid |
| Solids content | 54%–56% |
| Viscosity | 2,000–7,000 mPa·s at 23°C |
| pH | 4.0–6.0 |
| Minimum film-forming temperature | 1°C |
| Pigment and filler compatibility | Good |
| Electrolyte stability | Good |
When selecting an emulsion, check its compatibility with the other ingredients as well as its solids content, viscosity and minimum film-forming temperature.
Fire performance and trial evaluation
This formulation can serve as a starting point for trial coatings targeting two-hour fire resistance. Evaluate the finished coating in accordance with GB 14907–2018 and recheck performance if the formulation or application conditions change.
During trial batches, record ingredient proportions, order of addition and mixing conditions. Check the finished coating and the applied film against the intended application requirements so that results can be compared in subsequent trials.