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1. WO2007006622 - METHOD FOR PRODUCING A STORAGE-STABLE AND COLORLESS LIQUID POLYISOCYANATE COMPOSITION POSSESSING CARBODIIMIDE AND/OR URETONIMINE GROUPS

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CLAIMS

1. Method for producing a polyisocyanate composition possessing carbodiimide and/or uretonimine groups comprising the steps of
a) condensing a polyisocyanate in the presence of a catalyst selected from the group consisting of phospholenes, phospholidines and/or their oxides, and
b) stopping the condensation by adding a catalyst killer,
characterised in that said catalyst killer is adipoylchloride.
2. Method according to claim 1 wherein the molar ratio catalyst killer over catalyst is from 1 to 500, preferably from 5 to 300, most preferably from 10 to 200.
3. Method according to claim 1 or 2 wherein the catalyst is 3 -methyl- l-phenyl-2- phospholene- 1 -oxide.
4. Method according to any one of the preceding claims wherein the amount of catalyst is from 0.5 to 50 ppm, preferably from 1 to 30 ppm, most preferably from 2 to 15 ppm based on the weight of the polyisocyanate.
5. Method according to any one of the preceding claims wherein the amount of adipoylchloride catalyst killer is from 30 to 3000 ppm, preferably from 50 to 1000 ppm, most preferably from 80 to 500 ppm based on the weight of the polyisocyanate.

6. Method according to any one of the preceding claims wherein the polyisocyanate is an aromatic polyisocyanate.
7. Polyisocyanate composition possessing carbodiimide and/or uretonimine groups obtainable by the method as defined in any one of the preceding claims.
8. Polyisocyanate composition according to claim 7 having a Yellowness Index of 1 to

10, preferably from 2 to 7.
9. Use of a polyisocyanate composition as defined in claims 7 or 8 in the manufacture of foams, coatings, adhesives and elastomers.