Bayhydur® 304

Hydrophilically modified, aliphatic HDI-polyisocyanate for waterborne polymer dispersions. Corresponds to the following sections of the U.S. FDA’s guidelines Title 21 CFR: Section 175.105 “Adhesives”.

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Product Types

  • Hydrophilic polyisocyanate


No data available

General Characterization

Hydrophilically modified, aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI).
As the hardener/binder component for high-quality waterborne polymer dispersions and as an additive to improve the property level of waterborne coating and adhesive systems.
With respect to its composition, the product corresponds to the following sections of the U.S. FDA’s guidelines Title 21 CFR: Section 175.105 “Adhesives”.

Storage Conditions

- Storage in original sealed Covestro container.

- Recommended storage temperature: 0 - 30 °C.

- Protect from moisture, heat and foreign material.

General information: Hydrophilic isocyanates are very moisture-sensitive and react with water to form carbon dioxide and insoluble ureas. The containers must always be kept tightly closed. The access of water in all forms (moist air, solvents, moist containers) must be prevented, because the generation of carbon dioxide can lead to dangerous increases in pressure. Storage at higher temperatures will result in increase of color and viscosity.


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Packaging Type

No data available

Technical Properties & Datasheets


Property Name Test Method Unit Value
NCO content DIN EN ISO 11 909 % 18.2 ± 0.5
Monomeric HDI content DIN EN ISO 10 283 % by wt. < 0.15
Hazen color value DIN EN 1557 ≤ 60
Viscosity at 23 °C DIN EN ISO 3219/A.3 mPa*s 4,000 ± 1,500


Property Name Test Method Unit Value
Flash point DIN EN 22 719 °C 226
Equivalent weight approx. 230
Density DIN 53 217/3 g/ml approx. 1.16


Technical Data Sheet
Safety Data Sheet
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