Graft polymer and thermoreversibly cross-linked bitumen composition comprising said graft polymer

Abstract

The disclosure relates to a bitumen/polymer composition comprising at least one bitumen and at least one graft polymer, the grafts enabling the bitumen/polymer compositions to be thermoreversibly cross-linked. The disclosure also relates to the use of said bitumen/polymer compositions in fields of application relating to roads, especially in the production of asphalt binders, and in industrial fields of application. The disclosure further relates to the method for producing said thermoreversibly cross-linked bitumen/polymer compositions.

1 . A graft polymer comprising a polymer main chain and at least one side graft linked to the polymer main chain, the polymer main chain being obtained from at least one diene unit, the graft comprising a branched, linear or saturated hydrocarbon chain, having at least 18 carbon atoms. 
     
     
         2 . The graft polymer according to  claim 1  in which the branched, linear or saturated hydrocarbon chain of at least 18 carbon atoms has the general formula C n H 2n+1 , where n represents an integer greater than or equal to 18. 
     
     
         3 . The graft polymer according to  claim 1  in which the polymer results from the copolymerisation of conjugated diene units and aromatic monovinyl hydrocarbon units. 
     
     
         4 . The graft polymer according to  claim 1  in which the polymer main chain of the polymer comprises reactive double bonds, in particular pendant vinyl double bonds originating from the 1-2 addition of conjugated diene units, in particular butadiene units. 
     
     
         5 . The graft polymer according to  claim 1  in which the polymer has a content by weight of pendant vinyl double-bond units originating from the 1-2 addition of butadiene from 5% to 50%. 
     
     
         6 . The graft polymer according to  claim 1  in which the graft has the general formula C n H 2n+1 —XH where X represents a sulphur atom, an oxygen atom or the NH group and n represents an integer varying from 18 to 110. 
     
     
         7 . The graft polymer according to  claim 1  in which the graft has the general formula C n H 2n+1 —(OCH 2 CH 2 ) m —XH where X represents a sulphur atom, an oxygen atom or the NH group, n represents an integer varying from 18 to 110 and m represents an integer varying from 1 to 20. 
     
     
         8 . The graft polymer according to  claim 1  obtained by reaction between at least one double bond of polymer, in particular a pendant vinyl double bond originating from the 1-2 addition of a conjugated diene unit of polymer and a reactive function of a graft chosen from the thiol, alcohol or amine functions. 
     
     
         9 . The graft polymer according to  claim 1  comprising at least two grafts per main polymer chain. 
     
     
         10 . A use of at least one graft polymer according to  claim 1  in bitumen in order to obtain a bitumen/polymer composition. 
     
     
         11 . A bitumen/polymer composition comprising at least one bitumen and at least one polymer, in which the polymer is a graft polymer according to  claim 1 . 
     
     
         12 . A bitumen/polymer composition according to  claim 11  in which the content of the graft polymer by weight with respect to the bitumen is from 0.1 to 30%. 
     
     
         13 . A process for the ex situ preparation of bitumen/polymer compositions according to  claim 11  in which:
 a) a bitumen is introduced into a receiving vessel equipped with a mixer means, and the bitumen is taken to a temperature comprised between 90 and 220° C.,   b) from 0.1 to 30%, by mass of a graft polymer with respect to the mass of bitumen is introduced, and   c) the composition is heated at a temperature comprised between 90 and 220° C., under stirring, until a homogeneous final bitumen/polymer composition is obtained.   
     
     
         14 . A process for the in situ preparation of bitumen/polymer compositions according to  claim 11  in which:
 a) a bitumen is introduced into a receiving vessel equipped with a mixer means, and the bitumen is taken to a temperature between 90 and 220° C.,   b) from 0.1 to 30%, preferably 0.1 to 10% by mass of a polymer and from 0.1 to 30%, by mass of a graft with respect to the mass of bitumen are introduced, and   c) the composition is heated at a temperature comprised between 90 and 220° C., under stirring, until a homogeneous final bitumen/polymer composition is obtained.   
     
     
         15 . A use of bitumen/polymer compositions according to  claim 11  in order to produce a bituminous binder, in particular in anhydrous form, in the form of an emulsion or in the form of fluxed bitumen. 
     
     
         16 . A use of bitumen/polymer compositions according to  claim 11  in a mixture with aggregates for producing a surface dressing, a hot mix, a cold mix, a cold-cast mix, or an emulsion gravel.