Thermoplastic composition comprising: a first copolymer grafted by polyamide grafts and consisting of a polyolefin backbone containing a residue of at least one unsaturated monomer and a plurality of polyamide grafts, the polyamide grafts are attached to the polyolefin backbone by the residue of the unsaturated monomer comprising a function capable of reacting by a condensation reaction with a polyamide having at least one amine end group and/or at least one carboxylic acid end group, the residue of the unsaturated monomer is fixed to the backbone by grafting or copolymerization; characterized in that it comprises: • a second copolymer consisting of an elastomeric copolymer grafted by polyamide grafts and consisting of a polyolefin backbone selected from a maleicized ethylene-propylene copolymer, a maleicized ethylene-butene copolymer, a maleicized ethylene-hexene copolymer, a maleicized ethylene-octene copolymer, a maleicized ethylene-methyl acrylate copolymer, an ethylene-propylene-diene copolymer and a plurality of polyamide grafts; • a third component consisting of a polyamide, a polyethylene or a polypropylene, or a mixture thereof; and in that, the following weight ratios are satisfied: - between 10% and 30% by weight of the composition for the polyolefin backbone of the abovementioned first copolymer, - between 10% and 30% by weight of the composition for the polyolefin backbone of the abovementioned second copolymer, - between 5% and 35% by weight of the composition of polyamide grafts, fixed to the first and second copolymer, - between 30% and 60% by weight of the abovementioned third component. a first copolymer grafted by polyamide grafts and consisting of a polyolefin backbone containing a residue of at least one unsaturated monomer and a plurality of polyamide grafts, the polyamide grafts are attached to the polyolefin backbone by the residue of the unsaturated monomer comprising a function capable of reacting by a condensation reaction with a polyamide having at least one amine end group and/or at least one carboxylic acid end group, the residue of the unsaturated monomer is fixed to the backbone by grafting or copolymerization; • a second copolymer consisting of an elastomeric copolymer grafted by polyamide grafts and consisting of a polyolefin backbone selected from a maleicized ethylene-propylene copolymer, a maleicized ethylene-butene copolymer, a maleicized ethylene-hexene copolymer, a maleicized ethylene-octene copolymer, a maleicized ethylene-methyl acrylate copolymer, an ethylene-propylene-diene copolymer and a plurality of polyamide grafts; • a third component consisting of a polyamide, a polyethylene or a polypropylene, or a mixture thereof; and in that, the following weight ratios are satisfied: - between 10% and 30% by weight of the composition for the polyolefin backbone of the abovementioned first copolymer, - between 10% and 30% by weight of the composition for the polyolefin backbone of the abovementioned second copolymer, - between 5% and 35% by weight of the composition of polyamide grafts, fixed to the first and second copolymer, - between 30% and 60% by weight of the abovementioned third component. - between 10% and 30% by weight of the composition for the polyolefin backbone of the abovementioned first copolymer, - between 10% and 30% by weight of the composition for the polyolefin backbone of the abovementioned second copolymer, - between 5% and 35% by weight of the composition of polyamide grafts, fixed to the first and second copolymer, - between 30% and 60% by weight of the abovementioned third component.