Patent ID: 7579412

Claim:
A process for preparing carboxyl-terminated polyisobutenes, comprising: reacting ozone with a polyisobutene of formula I A(M-B) n (I) and carrying out a thermal after-treatment by heating the reaction product obtained from the ozone reaction to from 60 to 150° C., wherein A is a radical derived from a polymerization initiator, M is a polymer chain comprising repeating units of the formula II [CH 2 —C(CH 3 ) 2 ] (II), and B is a radical of the formula III or IV —CH 2 —CH═CH 2 (III) —CH═CR 1 R 2 (IV) wherein R 1 and R 2 are each H, C 1 -C 4 -alkyl or phenyl, and n is from 1 to 6, and wherein the thermal heat treatment of the reaction product obtained from the ozone reaction is optional when B is a radical of formula IV and R 1 and R 2 are phenyl.