Patent ID: 7932324

Claim:
A process for preparing a block polymer comprising at least one first block and at least one second block that are incompatible with each other and that have different glass transition temperatures (Tg), wherein the block polymer is not an elastomer, wherein the at least one first block has a Tg greater than or equal to 40° C. and is present in an amount ranging from 50% to 90% by weight of the block polymer, wherein the at least one second block has a Tg less than 20° C. and is present in an amount ranging from 5% to 45% by weight of the block polymer, wherein the at least one first and second blocks are linked together via an intermediate segment comprising at least one constituent monomer of the at least one first block and at least one constituent monomer of the at least one second block, wherein each of the at least one first and second blocks comprises at least one monomer chosen from acrylic acid, acrylic acid esters, methacrylic acid, and methacrylic acid esters, wherein said intermediate block is a random copolymer block, and wherein the block polymer has a polydispersity index I ranging from 2.8 to 6, the process comprising: introducing a portion of polymerization solvent into a suitable reactor and heating until an adequate temperature for polymerization is reached, once the polymerization temperature is reached, introducing the constituent monomers of the first block in the presence of an polymerization initiator, after a time T corresponding to a maximum degree of conversion of 90%, introducing the constituent monomers of the second block and the rest of the polymerization solvent, leaving the mixture to react for a time T′, then cooling the mixture to room temperature to obtain the polymer dissolved in the polymerization solvent.