| 简介 |
FIELD : chemistry.SUBSTANCE : invention relates to synthesis of isoprene rubber and can be used in the industry of synthetic rubber, tyres and industrial rubber goods. The method involves polymerisation of isoprene in the presence of a catalyst system based on a salt of a rare-earth element, organoaluminium compound, alkylaluminium chloride and conjugated diene. A stream of isoprene solution is cooled or heated from minus 25 to plus 50°C and mixed with the catalyst system. The first polymerisation stage is carried out at 10 to 50°C until 5 to 30% isoprene conversion. The final stage is carried out at 50 to 70°C. Triisobutylaluminium or diisobutylaluminium hydride is fed into the overflow line between the first and second reactor. The isoprene rubber consists of linear macromolecules, contains 96 to 99% cis-1, 4-branches, bonded in position 1.4-1.4. The isoprene rubber has the following fractions : 25 to 50% with molecular weight over 1000000, 2 to 10% with molecular weight from 1000000 to 100000, 40 to 60% with molecular weight from 100000 to 30000, 0 to 5% with molecular weight less than 30000. The fraction with molecular weight over 1000000 contains 96% or less cis-1, 4-branches. Fractions with other molecular weights contain over 96% cis-1, 4-branches.EFFECT : obtaining isoprene-based rubber, with high dynamic strength during repeated strain and tear resistance.2 cl, 2 tbl, 19 ex |
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