IPDI-based hardener.

Conventional polyurethane coatings with a medium solids content often use a favorable combination of hardeners derived from two different diisocyanates. A hexamethylene diisocyanate (HDI) hardener ensures good crosslinking and resistance properties of the resultant coatings, while an isophorone diisocyanate (IPDI) hardener accelerates physical drying. The company has now developed an IPDI-based hardener, Desmodur XP 2565, that is said to greatly reduce the solvent content of polyurethane coatings. High-solids coatings can now be formulated with particularly fast drying properties. In Desmodur XP 2565, the company is said to have found another answer to the growing demand for raw materials used in low-solvent, high-solids polyurethane coatings. The market is reacting to stricter regulations that aim to reduce emissions of volatile organic compounds. Waterborne polyurethane systems, ideal candidates for the new hardener, are also becoming increasingly popular because of their environmental friendliness, according to the company. Due to its low viscosity, the hardener can be mixed in the aqueous phase, but because it is not hydrophilically modified, it can be used to formulate aqueous coatings that are said to be particularly weather-stable and chemically resistant. (Bayer MaterialScience)

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