Process for producing low-monomer-content organic polyisocyanates

1. A process for producing polyisocyanates having a residual monomeric isocyanate content of less than 1.0% by weight, comprising:

1) reacting

A) an isocyanate component composed of at least 60% by weight of one or more diisocyanates and not more than 40% by weight of one or more monoisocyanates and/or one or more isocyanates having a functionality ≧3 with

B1) optionally a catalyst and/or

B2) optionally a reactive component

 in the form of droplets in a diluent C) at a temperature of 0 to 200° C. with oligomerization,

2) separating the reaction mixture into an isocyanate phase and a diluent phase;

3) optionally adding a catalyst poison D) before, during or after the phase separation; and

4) removing the polyisocyanate present in the isocyanate phase from the excess monomer.

2. Process according to claim 1 , wherein exclusively HDI, IPDI, 2,4′- and/or 4,4′-diisocyanatodicyclohexylmethane are used as component A).

3. Process according to claim 1 , wherein alkanes which are optionally fluorinated or perfluorinated are used as diluents C).

4. Process according to claim 3 , wherein perfluorooctane is used as alkane in C).

5. Process according to claim 1 , wherein a weight ratio of isocyanate component A) to diluent C) of 1:10 to 1:1 is set.

6. Process according to claim 5 , wherein the weight ratio is 1:5 to 1:2.

7. Process according to claim 1 , wherein the reaction is carried out continuously.