Method for the production of an isocyanate-group terminated polyoxazolidinone composition

A process for producing an isocyanate-group terminated polyoxazolidinone composition, the process comprising copolymerizing of a polyisocyanate compound (A) with a polyepoxide compound (B) in the presence of a catalyst (C), wherein the polyisocyanate compound (A) comprises two or more isocyanate groups and the polyepoxide compound (B) comprises two or more epoxy groups;

• wherein a molar ratio of the isocyanate groups of the polyisocyanate compound (A) to the epoxy groups of the polyepoxide compound (B) is larger than 2:1 and less than 25:1;
• and wherein the catalyst (C) is represented by the formula (I)
• [M(R1)(R2)(R3)(R4)]+nYn− (I)
• wherein M is phosphorous or antimony,
• wherein (R1), (R2), (R3), and (R4) are each, independently of one another, a linear or branched alkyl groups containing 1 to 22 carbon atoms, optionally substituted with one or more heteroatoms, heteroatom containing substituents, or a combination thereof[[;]], a cycloaliphatic groups containing 3 to 22 carbon atoms, optionally substituted with one or more heteroatoms, heteroatom containing substituents, or a combination thereof[[;]], a C1 to C3 alkyl-bridged cycloaliphatic groups containing 3 to 22 carbon atoms, optionally substituted with one or more heteroatoms, heteroatom containing substituents, or a combination thereof, or an aryl groups containing 6 to 18 carbon atoms, optionally substituted with one or more alkyl groups containing 1 to 10 carbon atoms one or more heteroatom containing substituents one or more heteroatoms, or a combination thereof, wherein Y is a halide, carbonate, nitrate, sulfate or phosphate anion, more preferred a and
• wherein n is an integer of 1, 2 or 3,
• and wherein the process is conducted in the absence of a solvent (E) with a boiling point higher than 200° C. at 1 bar (absolute).