madrid2i

Resumen

PROBLEM TO BE SOLVED: To provide a process for producing a hydrogenated polymer that makes easy and effective deactivation of a living polymer before the hydrogenation step possible and that has good characteristics, by producing a conjugated diene polymer or copolymer by solution polymerization in the presence of an alkyllithium, adding a specified deactivating compound to it, adding a hydrogenation catalyst to the mixture and keeping the resulting mixture under pressure of hydrogen. SOLUTION: The conjugated diene polymer or copolymer has an average molecular weight of 500-1,000,000 and is desirably a copolymer of a conjugated diene such as 1,3-butadiene with a vinylaromatic compound such as styrene. The deactivating compound used is selected among R-OH, R-COOH, R'n -SiCl4-n and R'n -Sn-Cl4-n . In the formulae, n=0-3; R is a 2-20C alkyl having a polar group; and R' is a 1-20C alkyl or a 6-20C aryl. It is desirably ethylene glycol or 2-methyl-2,4-pentanediol. It is used in an amount equivalent to that of the polymerization catalyst used.

Reivindicaciones

1. Process for producing a hydrogenated rubber comprising the following steps: A. polymerization in solution of one or more monomers in the presence of a lithium alkyl to produce polymers or copolymers of conjugated dienes. B. addition to the reaction mixture of a compound selected from the following classes: R-OH, R-COOH, R'<n>-Si-Cl <4-n> , R'<n>-Sn-Cl<4-n> with n comprised between 0 and 3, extremes included, in an amount of equivalents which is at least equal to the amount of polymerization catalyst, wherein R is a C<2>-C<20> alkyl group optionally containing one or more polar functional groups selected from C-OH, COOH and such that the compound has a solubility in water / solubility in hydogenation solvent ratio higher than 49 and/or boiling point higher than 110°C; R' is a C<1>-C<20> alkyl or C<6>-C<20> aryl. C. hydrogenation of the deactivated polymer by adding to the mixture a hydrogenation catalyst and maintaining the mixture under hydrogen pressure, in a continuous, semicontinuous or batch manner, using stirred, tubular or loop reactors. 2. The process according to claim 1, wherein in step b) the deactivating compound is selected from ethylene glycol and 2-methyl-2,4-pentanediol. 3. The process according to claim 1 or 2 wherein in step a) copolymers of a conjugated diene such as 1,3-butadiene or isoprene, with vinylaromatic compounds such as styrene and a-methylstyrene are prepared. 4. The process according to claim 3 wherein in step a) a butadiene-styrene block copolymer is prepared. 5. The process according to claims 1-4 wherein the average molecular weight of the polymer is from 500 to 1000000. 6. The process according to claims 1-5 wherein in step c) the catalyst used is a titanocene compound, optionally in the presence of a cocatalyst. 7. The process according to claim 5 wherein the catalyst used is selected from Cp<2>Ti(PhOR)<2> and Cp<2>Ti(CH<2>PPh<2>)<2>.

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