Water-dispersible isocyanate curing agent STD 268
Coating raw materials 2025-08-01
Product Description
STD 268 is a water dispersible polyisocyanate based on hexamethylene diisocyanate (HDI). In combination with waterborne polyurethane, polyacrylate, etc., it can be used for water-borne coatings and adhesive. After addition of STD 268, the ready-to-use mixture must be used within the pot life.
STD 268 can be diluted with the solvents, such as propylene glycol methyl ether acetate (PMA), propylene glycol diacetate (PGDA), butyl acetate, etc. Only PU grade
solvents (< 0.05% water) should be used and the solvents must be tested in advance by the user to determine suitability.
Properties
1.High gloss and high building up.
2.Excellent weather resistance.
Characteristic Data
(Typical values – not specifications)
|
Property |
Value |
Unit |
Test Method |
| Appearance | Colorless to yellowish transparent liquid | — | Visual |
| NCO content | 20.5 ± 0.5 | % | GB/T 12009.4-2016 |
| Viscosity | 5000 – 7000 | mPa·s | Brookfield LV, 63#/3 rpm,25 °C |
| Color (APHA) | < 80 | — | GB/T 1722-1992 |
| Monomeric isocyanate | ≤ 0.1 | % | GB/T 18446-2009 |
| Flash point | ~196 | °C | GB/T 5208 |
| Density | ~1.17 | g/cm³ | GB/T 4472-2011 |
Storage & Handling
The product should be stored in dry conditions above 5°C and below 35°C with the integrity of the packaging, and prevent direct sunlight. The validity of this product is for 12 months, performance assessment is recommended before use after shelf life. The product should be protected from freezing during storage. Water dispersible polyisocyanates are very moisture-sensitive and react with water to form carbon dioxide and insoluble ureas. The generation of carbon dioxide can lead to dangerous increases in pressure. The containers must always be kept tightly closed and the access of water in all forms must be prevented. It is suggested to use up once the package is open.
