Process for producing stable polymer

A process for the production of a stable NCO prepolymer having an NCO content of 2.5% by weight al6 and a viscosity at 100 ° C of <5000 mPas comprising: a) reacting (1) a polyisocyanate having one melting point greater than 70C with (2) one or more polyols, having an average molecular weight of 1000 to 3000 g / mol, one viscosidadmedida at 75 ° C of <700 mPas and a functionality of 1.95 to 2, 15, 1) optionally in the presence auxiliary desustancias and additives, at a temperature of 80 ° C to 240 ° C in a ratio of NCO to OH groups of 1.55: 1 to 2.35: 1 paraformar a prepolymer, and b) after obtaining a homogeneous and transparent melt (end of reaction a)) quenching elprepolimero formed in a) below 70 ° C in such a way that the residence time of the prepolymer a) in the temperature range between the temperature at the end of a ) and 130 ° C does not exceed 1/2 hour and B) in the temperature range from the tempera ture at the end of a) to 110 ° C does not exceed 1.5 hours and C) in the temperature range from the temperature at the end of a) to 90 ° C does not exceed 7.5 hours and D) in the temperature range from the temperature at the end of a) to 70C does not exceed 72 hours, in which unreacted polyisocyanate still present after cooling is not removed.