Abstract: A process for preparing a polyurethane polymer comprises the step of: I) mixing a first component (100) comprising a polyisocyanate with a second reactant component (200) comprising a compound having Zerewitinoff-active hydrogen atoms in a mixing vessel (300) to obtain a reaction mixture (400), wherein the first reactant component (100) and/or the second reactant component (200) are contacted with a catalyst bed (500) before they are mixed in the mixing vessel (300) and/or the reaction mixture (400) is contacted with a catalyst bed (500), wherein the catalyst bed (500) contains a catalyst reversibly sorbed on a substrate, the catalyst catalyses the reaction of isocyanate groups with themselves or with Zerewitinoff-active compounds and the catalyst is released into the first component (100), second component (200) or reaction mixture (400) that is in contact with the catalyst bed (500), such that a reaction mixture (410) containing the catalyst is obtained.

Abstract: A process for preparing a polyurethane polymer comprises the step of: I) mixing a first component (100) comprising a polyisocyanate with a second reactant component (200) comprising a compound having Zerewitinoff-active hydrogen atoms in a mixing vessel (300) to obtain a reaction mixture (400), wherein the first reactant component (100) and/or the second reactant component (200) are contacted with a catalyst bed (500) before they are mixed in the mixing vessel (300) and/or the reaction mixture (400) is contacted with a catalyst bed (500), wherein the catalyst bed (500) contains a catalyst reversibly sorbed on a substrate, the catalyst catalyses the reaction of isocyanate groups with themselves or with Zerewitinoff-active compounds and the catalyst is released into the first component (100), second component (200) or reaction mixture (400) that is in contact with the catalyst bed (500), such that a reaction mixture (410) containing the catalyst is obtained.