STYRENE-BUTADIENE POLYMERS WITH STYRENE GRADIENT AND METHODS FOR PRODUCTION THEREOF Russian patent published in 2013 - IPC C08F236/06 C08F297/02 C08F297/04 C08L53/02 

FIELD: chemistry.

SUBSTANCE: invention includes a method of conducting polymerisation to obtain a polymer containing styrene and 1,3-butadiene monomer units, where said method includes: (A) feeding less than 60 wt % of the total amount of butadiene used in polymerisation into a reactor containing all the amount of styrene used in polymerisation, and a solvent; (B) feeding at least one initiator into the reactor and providing conditions for the reaction to occur over a time t; (C) feeding the remaining amount of butadiene into the reactor in two or more separate feeds; and where for each subsequent feeding of butadiene, the amount of the fed butadiene is less than the amount of butadiene fed into the reactor immediately before said feeding, or is equal to the amount of butadiene fed into the reactor immediately before said feeding. For each butadiene feed, the butadiene is fed over a time t_nc and after each feed, the reaction is carried out over a time t_nr, where n is the number of butadiene feeds, and where the polymer contains polymer chains having higher styrene content in a direction towards the middle of the polymer chains, and lower styrene content at the ends of the chains. The invention includes a polymer, a composition for articles and an article.

EFFECT: obtaining a special rubber structure.

22 cl, 9 tbl, 2 dwg, 1 ex