METHOD FOR PREPARING BUTADIENE-STYRENE RUBBER Russian patent published in 2003 - IPC

FIELD: rubber industry. SUBSTANCE: invention relates to preparing synthetic rubbers, in part, butadiene- styrene rubber of solute polymerization used in production of tires, rubber-technical articles and other fields and can be used in petrochemical industry. Process of copolymerization is carried out for some steps. At the first step n-butyllithium taken as measured 20-60 moles per one ton of monomers and a modifying additive taken among the group including diethylene glycol dimethyl, diethyl, divinyl ester, methyl-, ethyl-, di-tetrahydrofurfuryl ester taken as measured for mole ratio to n-butyllithium in the ranges 0.1-0.8 are added to charge with initial concentration of monomers 10-20 wt.-% in the ratio butadiene : styrene in the range from 85:15 to 60:40 by mass and the polymerization process is carried out up to conversion 95%, not less. At the second step divinylbenzene is added taken as measured for mole ratio to n-butyllithium from 0.1 to 0.6, kept for at least 2 min. At the third step the same charge is fed additionally taken as measured for mass ratio to initial amount in the range from 1: 1 to 6:1 and modified additive taken among the group including potassium tetrahydrofurfurylate, styryl or nonyl, substituted potassium phenolate in toluene solution as measured for mole ratio potassium-lithium from 0.01 to 0.1 and process is carried out up to conversion 95%, not less, at temperature of each step 20-60 C. If necessary, at the fourth step styrene is added taken in the amount 3-15 wt.-% of total amount of comonomers fed to system on the first and third steps and process is carried out repeatedly up to conversion of styrene 95%, not less. Method ensures to obtain butadiene-styrene rubber with preferred content of 1,3-links of static or static-block structure (if styrene is added at the final step), broad index ММР and enhanced value of friction coefficient with wet surface. EFFECT: improved preparing method, valuable properties of rubber. 2 cl, 1 tbl, 9 ex