Patent attributes
Disclosed are polyurethane encapsulating compounds for embedding hollow fibers of filter elements, obtainable by mixing a polyol component (A) and an isocyanate component (B), including at least one aromatic isocyanate, to give a reaction mixture and reacting the mixture to completion to give the polyurethane encapsulating compound. The polyol component (A) includes at least one fatty-acid-based polyol (a1) having a hydroxyl number of greater than 50 to less than 500 mg KOH/g and a functionality of from 2-6, and at least one bismuth catalyst (a2), obtainable by mixing a bismuth carboxylate (a2-1) with an amine compound (a2-11) having at least one tertiary nitrogen atom and at least one isocyanate-reactive hydrogen atom. The molar ratio of bismuth to amine compound (a2-11) is 1:0.5-1:50. Also disclosed are methods for producing filter elements using the polyurethane encapsulating compounds and to uses of the polyurethane encapsulating compounds for the embedding of hollow fibers.
