Method for manufacturing a thermoplastic material made from semi-crystalline polyamide

1. A process for the manufacture of a thermoplastic material, in particular of a mechanical part based on said material, wherein the process comprises at least one stage of molding by injection or one stage of processing by extrusion of a polyamide composition for thermoplastic material or thermoplastic material composition, said material comprising a thermoplastic matrix based on at least one thermoplastic polymer, wherein:

said matrix thermoplastic polymer is a semicrystalline polyamide polymer with a glass transition temperature Tg of at least 90° C. and with a melting point Tm of less than or equal to 280° C., as respectively determined according to the standards ISO 11357-2:2013 and 11357-3:2013,

said composition comprises:

a) a reactive composition comprising at least one reactive polyamide prepolymer, said composition being a precursor composition of said polyamide polymer of said matrix,

or, as an alternative to a),

b) a nonreactive composition of at least one polyamide polymer, including the polymer resulting from a), said composition being that of said matrix thermoplastic polymer, and

said composition a) or b) comprises one or more polyamides which are prepolymers according to a) or which are polymers according to b), which comprise different amide units A and B and optionally amide units C and D, selected as follows:

A: is a predominant amide unit present at a molar content ranging from 55% to 85%, chosen from x.T units, where x is a linear C 9 to C 18 aliphatic diamine and where T is terephthalic acid,

B: is an amide unit different from A, which unit B is present at a molar content ranging from 15% to 45%, depending on the Tm of the polyamide based on unit A, and said amide unit B is chosen from x′.T units, where x′ is chosen from:

B1) a branched aliphatic diamine carrying a single methyl or ethyl branch (or branching) and having a main chain length different by at least two carbon atoms with respect to the main chain length of the diamine x of said associated unit A, or

B2) m-xylylenediamine (MXD) or

B3) a linear aliphatic diamine selected from the group consisting of C 4 , C 5 , and C 7 to C 18 aliphatic diamines, when, in the unit A, said diamine x is a linear C 11 to C 18 aliphatic diamine and x′ is a C 9 to C 18 diamine when, in the unit A, said diamine x is a C 9 or C 10 diamine, with the proviso that the unit B3 is chosen from linear C 4 , C 5 and C 7 to C 18 aliphatic diamine when, in said unit A, said diamine x is a linear C 12 aliphatic diamine,

C: optional amide unit different from A and from B, chosen from amide units based on a cycloaliphatic and/or aromatic structure or based on x′.T as defined for B but with x′ different from x′ for the unit B,

D: optional amide unit different from A, from B and from C when C is present and chosen from the aliphatic amide units resulting from:

C 6 to C 12 amino acids or lactams or their mixtures,

the reaction of a linear C 6 to C 18 aliphatic diacid and of a linear C 6 to C 18 aliphatic diamine or of their mixtures,

and under the condition that the sum of the molar contents of A+B+C+D is equal to 100%, said composition being devoid of reinforcing fibers.

2. The process of claim 1 , wherein said amide unit C is present and in partial replacement of B at a molar content ranging up to 25%, with respect to said unit B.

3. The process of claim 1 , wherein said unit D is present and in partial replacement of B at a molar content ranging up to 70%, with respect to said unit B.

4. The process of claim 1 , wherein the difference Tm−Tc between the melting point Tm and the crystallization temperature Tc of said matrix thermoplastic polymer does not exceed 50° C., as determined according to the standard 11357-3:2013.

5. The process of claim 1 , wherein the enthalpy of crystallization, measured by differential scanning calorimetry (DSC) according to the standard ISO 11357-3:2013, is greater than 40 J/g.

6. The process of claim 1 , wherein said amide unit A is present with a molar content ranging from 55% to 80%, with respect to all of the units of said polymer.

7. The process of claim 1 , wherein said unit B corresponds to x′.T with x′ chosen according to option B1).

8. The process of claim 1 , wherein said unit B corresponds to a linear aliphatic diamine according to option B3).

9. The process of claim 1 , wherein the units A and B are selected as follows:

for the unit A which is 9T, said unit B is selected from: 10T, 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, with a molar content of B ranging from 30% to 45%,

for the unit A which is 10T, said unit B is selected from: 9T, 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, with a molar content of B ranging from 25% to 45%,

for the unit A which is 11T, said unit B is selected from: 9T, 10T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, with a molar content of B ranging from 20% to 45%,

for the unit A which is 12T, said unit B is selected from: 9T, 10T, 11T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, with a molar content of B ranging from 20% to 45%.

10. The process of claim 9 , wherein the unit A is a 10T unit and the unit B is selected from: 9T, 11T, 12T, 13T, 14T, 15T, 16T, 17T and 18T, MPMD.T and MXD.T, with a molar content of B ranging from 25% to 45%.

11. The process of claim 7 , wherein a portion of the unit B which is up to 70 mol %, with respect to B, is replaced with a unit C and/or D.

12. The process of claim 1 , wherein said polyamide composition is a reactive prepolymer composition according to a) and precursor of said polyamide polymer of said matrix of the material.

13. The process of claim 12 , wherein said composition a) comprises at least one reactive prepolymer carrying, on the same chain, two end functional groups X′ and Y′ which are respectively coreactive with one another by condensation, with X′ and Y′ being amine and carboxyl or carboxyl and amine respectively.

14. The process of claim 12 , wherein said reactive composition a) comprises at least two polyamide prepolymers which are reactive with one another and which each respectively carry two identical end functional groups X′ or Y′, said functional group X′ of a prepolymer being able to react only with said functional group Y′ of the other prepolymer.

15. A process for the manufacture of a thermoplastic material, in particular of a mechanical part based on said material, wherein the process comprises at least one stage of molding by injection or one stage of processing by extrusion of a polyamide composition for thermoplastic material or thermoplastic material composition, said material comprising a thermoplastic matrix based on at least one thermoplastic polymer, wherein:

said matrix thermoplastic polymer is a semicrystalline polyamide polymer with a glass transition temperature Tg of at least 90° C. and with a melting point Tm of less than or equal to 280° C., as respectively determined according to the standards ISO 11357-2:2013 and 11357-3:2013,

said composition comprises:

a) a reactive composition comprising at least one reactive polyamide prepolymer, said composition being a precursor composition of said polyamide polymer of said matrix,

or, as an alternative to a),

b) a nonreactive composition of at least one polyamide polymer, including the polymer resulting from a), said composition being that of said matrix thermoplastic polymer, and

said composition a) or b) comprises one or more polyamides which are prepolymers according to a) or which are polymers according to b), which comprise different amide units A and B and optionally amide units C and D, selected as follows:

A: is a predominant amide unit present at a molar content ranging from 55% to 85%, chosen from x′.T units, where x is a linear C 9 to C 18 aliphatic diamine and where T is terephthalic acid,

B: is an amide unit different from A, which unit B is present at a molar content ranging from 15% to 45%, depending on the Tm of the polyamide based on unit A, and said amide unit B is chosen from x′.T units, where x′ is chosen from:

B1) a branched aliphatic diamine carrying a single methyl or ethyl branch (or branching) and having a main chain length different by at least two carbon atoms with respect to the main chain length of the diamine x of said associated unit A, or

B2) m-xylylenediamine (MXD) or

B3) a linear C 4 to C 18 aliphatic diamine when, in the unit A, said diamine x is a linear C 11 to C 18 aliphatic diamine and x′ is a C 9 to C 18 diamine when, in the unit A, said diamine x is a C 9 or C 10 diamine, with the proviso that the unit B3 is chosen from linear C 4 , C 5 and C 7 to C 18 aliphatic diamine when, in said unit A, said diamine x is a linear C 12 aliphatic diamine,

C: optional amide unit different from A and from B, chosen from amide units based on a cycloaliphatic and/or aromatic structure or based on x′.T as defined for B but with x′ different from x′ for the unit B,

D: optional amide unit different from A, from B and from C when C is present and chosen from the aliphatic amide units resulting from:

C 6 to C 12 amino acids or lactams or their mixtures,

the reaction of a linear C 6 to C 18 aliphatic diacid and of a linear C 6 to C 18 aliphatic diamine or of their mixtures,

and under the condition that the sum of the molar contents of A+B+C+D is equal to 100%,

said composition being devoid of reinforcing fibers,

wherein said polyamide composition is a reactive prepolymer composition according to a) and precursor of said polyamide polymer of said matrix of the material, and

wherein said composition a) or precursor composition comprises:

a1) at least one prepolymer of said thermoplastic polyamide polymer, carrying n end reactive functional groups X, chosen from: —NH 2 , —CO 2 H and —OH, with n being from 1 to 3, and

a2) at least one chain extender Y-A′-Y, with A′ being a hydrocarbon biradical of nonpolymeric structure, carrying 2 identical end reactive functional groups Y, which are reactive by polyaddition with at least one functional group X of said prepolymer a1).

16. The process of claim 12 , wherein said reactive prepolymers of said composition a) have a number-average molecular weight Mn ranging from 500 to 10,000, as determined by potentiometric titration.

17. A process for the manufacture of a thermoplastic material, in particular of a mechanical part based on said material, wherein the process comprises at least one stage of molding by injection or one stage of processing by extrusion of a polyamide composition for thermoplastic material or thermoplastic material composition, said material comprising a thermoplastic matrix based on at least one thermoplastic polymer, wherein:

said matrix thermoplastic polymer is a semicrystalline polyamide polymer with a glass transition temperature Tg of at least 90° C. and with a melting point Tm of less than or equal to 280° C., as respectively determined according to the standards ISO 11357-2:2013 and 11357-3:2013,

said composition comprises:

a) a reactive composition comprising at least one reactive polyamide prepolymer, said composition being a precursor composition of said polyamide polymer of said matrix,

or, as an alternative to a),

b) a nonreactive composition of at least one polyamide polymer, including the polymer resulting from a), said composition being that of said matrix thermoplastic polymer, and

said composition a) or b) comprises one or more polyamides which are prepolymers according to a) or which are polymers according to b), which comprise different amide units A and B and optionally amide units C and D, selected as follows:

A: is a predominant amide unit present at a molar content ranging from 55% to 85%, chosen from x.T units, where x is a linear C 9 to C 18 aliphatic diamine and where T is terephthalic acid,

B: is an amide unit different from A, which unit B is present at a molar content ranging from 15% to 45%, depending on the Tm of the polyamide based on unit A, and said amide unit B is chosen from x′.T units, where x′ is chosen from:

B1) a branched aliphatic diamine carrying a single methyl or ethyl branch (or branching) and having a main chain length different by at least two carbon atoms with respect to the main chain length of the diamine x of said associated unit A, or

B2) m-xylylenediamine (MXD) or

B3) a linear C 4 to C 18 aliphatic diamine when, in the unit A, said diamine x is a linear C 11 to C 18 aliphatic diamine and x′ is a C 9 to C 18 diamine when, in the unit A, said diamine x is a C 9 or C 10 diamine, with the proviso that the unit B3 is chosen from linear C 4 , C 5 and C 7 to C 18 aliphatic diamine when, in said unit A, said diamine x is a linear C 12 aliphatic diamine,

C: optional amide unit different from A and from B, chosen from amide units based on a cycloaliphatic and/or aromatic structure or based on x′.T as defined for B but with x′ different from x′ for the unit B,

D: optional amide unit different from A, from B and from C when C is present and chosen from the aliphatic amide units resulting from:

C 6 to C 12 amino acids or lactams or their mixtures,

the reaction of a linear C 6 to C 18 aliphatic diacid and of a linear C 6 to C 18 aliphatic diamine or of their mixtures,

and under the condition that the sum of the molar contents of A+B+C+D is equal to 100%,

said composition being devoid of reinforcing fibers,

wherein said polyamide composition is a reactive prepolymer composition according to a) and precursor of said polyamide polymer of said matrix of the material, and

wherein X is NH 2 or OH, and Y is chosen from an oxazinone and an oxazolinone.

18. A process for the manufacture of a thermoplastic material, in particular of a mechanical part based on said material, wherein the process comprises at least one stage of molding by injection or one stage of processing by extrusion of a polyamide composition for thermoplastic material or thermoplastic material composition, said material comprising a thermoplastic matrix based on at least one thermoplastic polymer, wherein:

said matrix thermoplastic polymer is a semicrystalline polyamide polymer with a glass transition temperature Tg of at least 90° C. and with a melting point Tm of less than or equal to 280° C., as respectively determined according to the standards ISO 11357-2:2013 and 11357-3:2013,

said composition comprises:

a) a reactive composition comprising at least one reactive polyamide prepolymer, said composition being a precursor composition of said polyamide polymer of said matrix,

or, as an alternative to a),

b) a nonreactive composition of at least one polyamide polymer, including the polymer resulting from a), said composition being that of said matrix thermoplastic polymer, and

said composition a) or b) comprises one or more polyamides which are prepolymers according to a) or which are polymers according to b), which comprise different amide units A and B and optionally amide units C and D, selected as follows:

A: is a predominant amide unit present at a molar content ranging from 55% to 85%, chosen from x.T units, where x is a linear C 9 to C 18 aliphatic diamine and where T is terephthalic acid,

B: is an amide unit different from A, which unit B is present at a molar content ranging from 15% to 45%, depending on the Tm of the polyamide based on unit A, and said amide unit B is chosen from x′.T units, where x′ is chosen from:

B1) a branched aliphatic diamine carrying a single methyl or ethyl branch (or branching) and having a main chain length different by at least two carbon atoms with respect to the main chain length of the diamine x of said associated unit A, or

B2) m-xylylenediamine (MXD) or

B3) a linear C 4 to C 18 aliphatic diamine when, in the unit A, said diamine x is a linear C 11 to C 18 aliphatic diamine and x′ is a C 9 to C 18 diamine when, in the unit A, said diamine x is a C 9 or C 10 diamine, with the proviso that the unit B3 is chosen from linear C 4 , C 5 and C 7 to C 18 aliphatic diamine when, in said unit A, said diamine x is a linear C 12 aliphatic diamine,

C: optional amide unit different from A and from B, chosen from amide units based on a cycloaliphatic and/or aromatic structure or based on x′.T as defined for B but with x′ different from x′ for the unit B,

D: optional amide unit different from A, from B and from C when C is present and chosen from the aliphatic amide units resulting from:

C 6 to C 12 amino acids or lactams or their mixtures,

the reaction of a linear C 6 to C 18 aliphatic diacid and of a linear C 6 to C 18 aliphatic diamine or of their mixtures,

and under the condition that the sum of the molar contents of A+B+C+D is equal to 100%,

said composition being devoid of reinforcing fibers,

wherein said polyamide composition is a reactive prepolymer composition according to a) and precursor of said polyamide polymer of said matrix of the material, and

wherein X is CO 2 H and Y is chosen from an epoxy and an oxazoline.

19. The process of claim 18 , wherein X is CO 2 H and Y-A′-Y is chosen from phenylenebisoxazolines.

20. A mechanical part of thermoplastic material, wherein the part results from the use of at least one composition according to claim 1 or from the use of a nonreactive polyamide polymer according to said composition b) or a polymer capable of being obtained from a reactive composition according to said composition a).

21. The part of claim 20 , wherein the part concerns mechanical parts for applications in the motor vehicle industry, cooling devices or devices for transporting or transferring fuels or fluids.

22. The part of claim 20 , wherein the part concerns mechanical parts for applications in the electrical or electronics industry.

23. The process of claim 1 , wherein the reactive composition consists of the at least one reactive polyamide prepolymer.