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


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General Characterization

Bayhydur 304 is a 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.

Storage Conditions

Bayhydur 304 should be stored in tightly sealed original containers and protected from moisture, heat, and foreign materials. 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. Recommended storage temperature is 0º-30ºC.


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Packaging Type

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Technical Properties & Datasheets

Property Name Test Method Unit Value
Viscosity at 23^oC mPa∙s 2,500 - 5,500
Monomeric HDI % < 0.15
Hazen color value ≤ 60
NCO content % 17.7 - 18.7

Property Name Test Method Unit Value
Flash point °C 226
Equivalent weight approx. 230
Density g/ml approx. 1.16


Technical Data Sheet
Safety Data Sheet
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