Ethylene and butadiene copolymer having a homogeneous microstructure

Abstract

An ethylene/butadiene copolymer comprising statistically distributed ethylene units and butadiene units is provided. The molar fraction of the ethylene units in the copolymer is greater than or equal to 50%, relative to the total number of moles of ethylene and butadiene units. The microstructure of the copolymer is homogeneous. A process for preparing such a copolymer and also the uses of this copolymer, in particular in rubber compositions for tires is also provided.

1 . An ethylene/butadiene copolymer comprising, statistically distributed, ethylene units and butadiene units, a molar fraction of ethylene units in said copolymer being greater than or equal to 50%, relative to the total number of moles of ethylene and butadiene units, wherein said copolymer has a homogeneous microstructure and thus the molar concentration of each of the units is constant all along the chain of said copolymer. 
     
     
         2 . The ethylene/butadiene copolymer according to  claim 1 , wherein the molar fraction of ethylene units ranges from 50 mol % to 95 mol %, relative to the total number of moles of ethylene and butadiene units. 
     
     
         3 . The ethylene/butadiene copolymer according to  claim 1 , wherein the molar fraction of ethylene units ranges from 70 mol % to 88 mol %, relative to the total number of moles of ethylene and butadiene units. 
     
     
         4 . The ethylene/butadiene copolymer according to  claim 1 , which is an elastomer. 
     
     
         5 . The ethylene/butadiene copolymer according to  claim 1 , which is a semicrystalline polymer. 
     
     
         6 . A composition comprising a copolymer according to  claim 1 . 
     
     
         7 . An ethylene/butadiene copolymer obtained by a process comprising a solution polymerization, in a hydrocarbon solvent, at a temperature of between 0° C. and 200° C., of ethylene and butadiene in the presence of a catalytic system, in a stirred reactor, wherein the polymerization is carried out at constant temperature and at constant ethylene pressure and constant butadiene pressure, wherein the ethylene and butadiene are injected continuously into the reactor and wherein, in the reaction medium, at each instant of polymerization, ethylene and butadiene concentrations are constant, and wherein the microstructure of the copolymer is homogeneous. 
     
     
         8 . The ethylene/butadiene copolymer according to  claim 7 , which is an elastomer. 
     
     
         9 . The ethylene/butadiene copolymer according to  claim 7 , which is a semicrystalline polymer. 
     
     
         10 . A composition comprising a copolymer according to  claim 7 .