Thermoplastic polymeric compositions

1. Thermoplastic polymeric composition comprising the following compounds:

(A) from 1 to 97% by weight, with respect to the total weight of the composition, of a polyamide,

(B) from 1 to 97% by weight, with respect to the total weight of the composition, of a copolymer containing a rubber onto which are grafted acrylonitrile and a styrenic compound selected from the group consisting of styrene and α-methylstyrene, the copolymer containing from 10 to 90% by weight of rubber,

(C) from 0.5 to 97% by weight, with respect to the total weight of the composition, of a styrene-maleimide copolymer having functional groups selected from the group consisting of carboxylic acids and acid anhydrides,

(D) from 0.5 to 97% by weight, with respect to the total weight of the composition, of a styrene-maleimide copolymer,

(E) from 0 to 50% of an impact modifier, and

(F) from 0 to 50% by weight of a maleic-anhydride-grafted styrene-ethylene-butylene-styrene copolymer,

wherein the proportion of polyamide (A) by weight is greater than the proportion of copolymer (B) by weight.

2. Composition according to claim 1 , wherein the copolymer B is an acrylonitrile-styrene-butadiene copolymer.

3. Composition according to claim 2 , wherein the impact modifier is an elastomer.

4. Composition according to claim 3 , wherein the elastomer is an elastomer grafted with functional groups selected from the group consisting of carboxylic acids and acid anhydrides.

5. Composition according to claim 1 , wherein the functional groups of the copolymer C are obtained by copolymerization in the presence of maleic anhydride.

6. Composition according to claim 1 , wherein the proportion by weight of the functional groups in the styrene-maleimide copolymer, with respect to the total weight of styrene-maleimide copolymer present in the composition, is between 0.1 and 3%.

7. Composition according to claim 1 , wherein the maleimide groups present in the copolymers (C) and (D) are phenylmaleimide groups.

8. Composition according to claim 1 , wherein the impact modifier is selected from the group consisting of maleic-anhydride-grafted ethylene-propylene rubber, maleic-anhydride-grafted ethylene-propylene-diene rubber, maleic-anhydride-grafted polyethylenes, and maleic-anhydride-grafted polypropylene.

9. Composition according to claim 1 , wherein the polyamide is selected from the group consisting of nylon-6, nylon-11, nylon-12, the copolyamide nylon-6/6,36, copolymers of nylon-6, nylon-11 and nylon-12 and mixtures of said polyamides.

10. Composition according to claim 1 , wherein the proportion of polyamide by weight is greater than the total of the proportions of compounds (C) and (D).

11. Composition according to claim 1 , wherein the proportions of the compounds by weight are the following:

30 to 70% of polyamide (A)

20 to 40% of compound (B)

5 to 20% of compound (C)

1 to 10% of compound (D)

0 to 20% of compound (B)

0.5 to 10% of compound (F).