Modified polymers with a high proportion of cis-position double bonds

A process for producing polymers that are modified along the polymer chain comprising conjugated dienes or conjugated dienes and vinyl-aromatic compounds and vinyl-aromatic compounds having a content of vinyl-aromatic compounds of up to 60 wt. %, a proportion of cis-position double bonds of ≧92%, a mean molecular weight (Mw) of 50,000 to 1,500,000 g/mole, a gel content of ≦5% and a degree of modification of 0.05 to 20 wt. %, comprising the steps of

• (a) polymerizing the conjugated dienes or the conjugated dienes and vinyl-aromatic compounds at temperatures of −30° to 130° C. in the presence of rare earth metal compounds and in the presence of an inert, aliphatic solvent, the water content of the reaction mixture being ≦1,000 ppm,
• (b) reacting the resulting polymers containing 1.0 to 1,000 mmole/100 g of polymer of active hydrogen atoms with 0.1 to 200 mmole based on 100 g of polymer, of organometallic compounds or with the metals themselves, the metals of the organometallic compounds being selected from the group of alkali metals or alkaline earth metals, in the presence of 0.1 to 200 mmole, based on 100 g of polymer, of compounds capable of forming co-ordinate bonds with the metallized polymer anions, at temperatures of 20° to 2000° C. and
• (c) reacting at temperatures of 0° to 200° C. the stabilized polymer anions obtained with 0.01 to 200 mmole, based on 100 g of polymer, of organic compounds that contain a group capable of reacting with the polymer anions and at least one polar group in the molecule, wherein the polar groups contain elements of main groups III, IV, V, VI or VII of the PSE or combinations thereof, and the groups capable of reacting with the polymer anions are selected from carbonyl groups, acid chloride groups, metal halide groups, sulfenyl groups, sulfonyl groups, aminochloride groups, groups containing reactive double bonds, epoxide groups, isocyanate groups, nitrile groups and organosilicon and organotin groups, in the presence of aprotic, organic solvents.