| abstract |
The invention relates to an isocyanate group-containing polyether urethane polymer having an NCO content in the range from 1.3 to 1.9 wt% and a content of monomeric diisocyanates of not more than 0.5 wt%, derived from the reaction of at least one monomeric aromatic diisocyanate and a polyether triol having an average OH functionality in the range from 2.2 to 2.6, an OH number in the range from 25 to 32 mg KOH/g in an NCO/OH ratio of at least 3:1 and subsequent removal of a majority of the monomeric diisocyanates by means of a suitable separation process, and moisture-curing polyurethane compositions having a content of monomeric diisocyanates of less than 0.1 wt% containing said polymer. The polymer according to the invention allows very storage-stable moisture-curing polyurethane compositions, which are safe to handle even without special protective measures, are easy to process, have a long open time, cure rapidly to provide an elastic material of high extensibility and elasticity with high strength, high tear propagation resistance, good low-temperature flexibility, good adhesion properties and high resistance, in particular with respect to heat and UV radiation. Such polyurethane compositions are in particular suitable as elastic adhesives, sealants, and coatings. |