Process for the preparation of organic polyisocyanates containing urea groups

Claim 2

A process for the preparation of polyisocyanates containing urea groups comprising (a) introducing an organic polyisocyanate of the formula R.sub.1 (NCO).sub.2 wherein R 1 is an aliphatic hydrocarbon group having from 2 to 18 carbon atoms, an aromatic hydrocarbon group having from 6 to 15 carbon atoms, an araliphatic hydrocarbon group having from 8 to 15 carbon atoms or a cycloaliphatic hydrocarbon group having from 4 to 15 carbon atoms, at least two carbon atoms in each hydrocarbon group being situated between the two isocyanate groups, into a reaction vessel, and (b) injecting an organic polyamine of the formula R.sub.2 (NH.sub.2).sub.2 wherein R 2 is an aliphatic hydrocarbon group having from 4 to 11 carbon atoms or an aromatic hydrocarbon group having from 6 to 15 carbon atoms, into the organic polyisocyanate in the reaction vessel at a pressure of from about 2 to 1000 bar through a straight jet nozzle having an internal diameter of from about 0.01 to 5 mm wherein (i) the polyisocyanate/polyamine NCO/NH 2 molar ratio is at least about 4:1, and (ii) the temperature in the reaction vessel is between about 20° C. to 180° C.

Claim 3

A process for the preparation of a polyisocyanate containing urea groups comprising (a) introducing an organic polyisocyanate of the formula R.sub.1 (NCO).sub.2 wherein R 1 is an aromatic hydrocarbon group having from 6 to 15 carbon atoms, into a reaction vessel, and (b) injecting an organic polyamine of the formula R.sub.2 (NH.sub.2).sub.2 wherein R 2 is an aliphatic hydrocarbon group having from 4 to 11 carbon atoms or an aromatic hydrocarbon group having from 6 to 15 carbon atoms, into the organic polyisocyanate in the reaction vessel at a pressure of from about 2 to 1000 bar through a straight jet nozzle having an internal diameter of from about 0.01 to 5 mm wherein (i) the polyisocyanate/polyamine NCO/NH 2 molar ratio is at least about 4:1, (ii) the temperature in the reaction vessel is between about 20° C. to 180° C.

Claim 4

A process for the preparation of a polyisocyanate containing urea groups comprising (a) introducing an organic polyisocyanate of the formula R.sub.1 (NCO).sub.2 wherein R 1 is an aromatic hydrocarbon group having from 6 to 15 carbon atoms, into a reaction vessel, and (b) injecting an organic polyamine of the formula R.sub.2 (NH.sub.2).sub.2 wherein R 2 is an aliphatic hydrocarbon group having from 4 to 11 carbon atoms or an aromatic hydrocarbon group having from 6 to 15 carbon atoms, into the organic polyisocyanate in the reaction vessel at a pressure of from about 2 to 1000 bar through a straight jet nozzle having an internal diameter of from about 0.01 to 5 mm wherein (i) the polyisocyanate/polyamine NCO/NH 2 molar ratio is at least about 4:1, (ii) the temperature in the reaction vessel is between about 20° C. to 180° C.

Claim 5

The process of claim 2, wherein the polyisocyanate containing urea groups is prepared as a dispersion in the excess organic polyisocyanate.

Claim 6

The process of claim 2, wherein the NCO/NH 2 molar ratio is between about 4:1 and 1000:1.

Claim 7

The process of claim 2, wherein the NCO/NH 2 ratio is between about 5:1 and 25:1.

Claim 8

The process of claim 2, wherein (a) the distance from the nozzle to the wall of the reaction vessel opposite the nozzle measured in the direction of the injection jet is at least about 100 times the diameter of the nozzle, (b) the smallest lateral distance from the injection jet to an internal wall of the reaction vessel is at least about 25 times the diameter of the nozzle, and (c) the polyamine is injected into the polyisocyanate in the reaction vessel at a relative velocity of at least 5 m/sec.

Claim 9

A process for the preparation of polyisocyanates containing urea groups dispersed in polyisocyanates which are free from urea and biuret groups, by the reaction of organic diisocyanates of the formula R.sub.1 (NCO).sub.2 wherein R 1 is an aromatic hydrocarbon group having from 6 to 15 carbon atoms, with organic polyamines of the formula R.sub.2 (NH.sub.2).sub.2 wherein R 2 is an aliphatic hydrocarbon group having from 4 to 11 carbon atoms or an aromatic hydrocarbon group having from 6 to 15 carbon atoms, using an NCO/NH 2 molar ratio of at least about 4:1, the polyisocyanate used in excess, which serves both as reactant and solvent, being first introduced into the reaction vessel, whereas the polyamine, which is used in less than the equivalent amount, is introduced into the polyisocyanate in the reaction vessel at a temperature in the range from about 20° to 180° C., characterized in that (a) the polyisocyanate component, which is used in excess, is first introduced into the reaction vessel; (b) the polyamine component, which is used in less than the equivalent quantity, is injected at a pressure of from about 2 to 1000 bar into the polyisocyanate component in the reaction vessel at a relative velocity of at least about 5 m/sec by means of a straight jet nozzle which has an internal diameter of from about 0.01 to 5 mm; and (c) the dimensions of the reaction vessel are chosen so that the distance from the nozzle to the internal wall of the reaction vessel measured in the direction of the injection jet is at least about 100 times the diameter of the nozzle, and the shortest distance from the nozzle jet to the lateral wall of the reaction vessel is at least about 25 times the diameter of the nozzle.

Claim 10

A process for the preparation of polyisocyanates containing urea groups dispersed in polyisocyanates which are free from urea and biuret groups, by the reaction of organic diisocyanates of the formula R.sub.1 (NCO).sub.2 wherein R 1 is an aromatic hydrocarbon group having from 6 to 15 carbon atoms, with organic polyamines of the formula R.sub.2 (NH.sub.2).sub.2 wherein R 2 is an aliphatic hydrocarbon group having from 4 to 11 carbon atoms or an aromatic hydrocarbon group having from 6 to 15 carbon atoms, using an NCO/NH 2 molar ratio of at least about 4:1, the polyisocyanate used in excess, which serves both as reactant and solvent, being first introduced into the reaction vessel, whereas the polyamine, which is used in less than the equivalent amount, is introduced into the polyisocyanate in the reaction vessel at a temperature in the range from about 20° to 180° C., characterized in that (a) the polyisocyanate component, which is used in excess, is first introduced into the reaction vessel; (b) the polyamine component, which is used in less than the equivalent quantity, is injected at a pressure of from about 2 to 1000 bar into the polyisocyanate component in the reaction vessel at a relative velocity of at least about 5 m/sec by means of a straight jet nozzle which has an internal diameter of from about 0.01 to 5 mm; and (c) the dimensions of the reaction vessel are chosen so that the distance from the nozzle to the internal wall of the reaction vessel measured in the direction of the injection jet is at least about 100 times the diameter of the nozzle, and the shortest distance from the nozzle jet to the lateral wall of the reaction vessel is at least about 25 times the diameter of the nozzle.