Covestro Bayhydur XP 2655 hydrophilic HDI polyisocyanate, low viscosity and easy to disperse

Type Hydrophilic aliphatic polyisocyanate based on hexamethylene diisocyanate (HDI), used as the curing agent component of water-based two-component polyurethane systems

Supply form 100 %





Test method

NCO Content

20.3 – 21.3


M105 -ISO 11909


3,500 ± 1,000

mPa ·s

M014 -ISO 3219/A.3

HazenColor value

< 60

<span style="font-fami��Water-based systems need to have a combination of stability and chemical resistance. Although the curing agent is relatively weakly hydrophilic, it emulsifies easily in the aqueous phase, even at the low shear forces common in commercial applications. Coatings prepared using this product can form a high-gloss, low-haze film.
Generally, when mixed with a hydrophilic curing agent, especially an ionic hydrophilic polyol dispersion, it can be diluted with water in advance or a small amount of organic co-solvent can be added to control the viscosity increase. Due to the balance between moderate hydrophilicity and high functionality, waterborne two-component polyurethane coatings prepared using Bayhydur XP 2655 are fast drying and hardening, and the resulting films have high final hardness and excellent chemical resistance characteristics. Bayhydur combination agent.
After adding Bayhydur XP 2655, the two-component paint to be used must be used within the pot life. Pot life is affected by polymer content and other components (such as resins, thickeners, plasticizers, etc.). In many dispersions, the end of the pot life (usually a few hours) does not show gelling.

– Store in Covestro sealed containers;
– Recommended storage temperature: 0-30°C;
– Protection against moisture, heat and foreign substances.

General Information :Hydrophilic isocyanates are very sensitive to moisture and react with water to form carbon dioxide and water-insoluble urea. Therefore must be stored in airtight containers. All forms of water (humid air, solvents, moist containers) must be prevented because the production of carbon dioxide can cause a dangerous increase in pressure. Storage at high temperatures will cause a slight increase in viscosity and color.

Storage Time
Provided that the product is stored in full compliance with the requirements in the “Storage” clause above and handled appropriately, the product shall comply with the requirements within 6 months from the date of shipment stated on the transport document The specifications or characteristic values ​​stated in the “Specifications or Characteristic Values” clause above (as appropriate). If a product exceeds the above 6-month period, it does not mean that it no longer meets the specifications or the values ​​set in the characteristic values. However, it is recommended that products more than 6 months from the date of shipment be tested before use to confirm whether they still meet the values ​​set in the specifications or characteristic values. The manufacturer does not make any commitments for products that are more than 6 months from the date of shipment, nor does it assume any responsibility or liability for products that do not meet the specifications or the set values ​​in the characteristic values.