Thermoplastic elastomer compositions

1. A thermoplastic elastomer composition comprising 10-50 wt % of at least one aliphatic polyamide; 1-10 wt % of at least one graft-modified ethylene-olefin elastomeric copolymer; 1-10 wt % of at least one graft-modified ethylene-propylene elastomeric copolymer; and 40-80 wt % of at least one polyether-ester-amide block copolymer (TPEA) having a shore D of 50-60 (as measured in accordance with ASTM D2240), with the total weight percent of all components in the composition totaling 100%, wherein graft modified ethylene-olefin elastomeric copolymer and graft-modified ethylene propylene elastomeric copolymer are different from each other wherein the composition has a higher abrasion resistance than both of the polyether-ester-amide block copolymer as well as a composition formed by melt blending the two graft-modified copolymers and polyamide in the amounts present in the composition.

2. The composition of claim 1 wherein the graft-modified ethylene-olefin elastomeric copolymer comprises one or more functional groups and has a grafting degree of 0.01 to 5 wt %.

3. The composition of claim 2 wherein the graft-modified ethylene-olefin elastomeric copolymer has a grafting degree of 0.1 to 3 wt %.

4. The composition of claim 3 wherein the ethylene-olefin elastomeric copolymer comprises 5 to 45 wt % of copolymerized units of C 4-10 olefin selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 2-heptene, 2-butene, 2-octene, 2-hexene, and combinations of two or more thereof; the remainder is copolymerized units of ethylene; and the total amount of copolymerized units is 100 wt %.

5. The composition of claim 4 wherein the graft-modified ethylene-olefin elastomeric copolymer comprises has a grafting degree of 0.2 to 1 wt %.

6. The composition of claim 5 wherein the graft-modified ethylene-olefin elastomeric copolymer is a maleic anhydride grafted ethylene-octene elastomeric copolymer.

7. The composition of claim 3 wherein the ethylene-propylene elastomeric copolymer comprises 20 to 60 wt % of copolymerized units of propylene; the remainder is copolymerized units of ethylene; and the total amount of copolymerized units is 100 wt %.

8. The composition of claim 7 wherein the graft-modified ethylene-olefin elastomeric copolymer is a maleic anhydride grafted ethylene-octene elastomeric copolymer; and the ethylene-propylene elastomeric copolymer comprises 25 to 55 wt % of copolymerized units of propylene.

9. The composition of claim 7 wherein the ethylene-propylene elastomeric copolymer further comprises 0 to 25 wt % of copolymerized units of a C 5-10 non-conjugated diene.

10. The composition of claim 9 wherein the ethylene-propylene elastomeric copolymer further comprises 0 to 15 wt % copolymerized units of the C 5-10 non-conjugated diene.

11. The composition of claim 10 wherein the graft-modified ethylene-propylene elastomeric copolymer is a maleic anhydride grafted EPDM rubber.

12. The composition of claim 4 wherein the aliphatic polyamide is selected from the group consisting of polyamide 4,6; polyamide 6; polyamide 6,6; polyamide 6,10; polyamide 6,12; polyamide 6,13; polyamide 6,14; polyamide 6,15; polyamide 6,16; polyamide 9,10; polyamide 9,12; polyamide 9,13; polyamide 9,14; polyamide 9,15; polyamide 9,36; polyamide 10,10; polyamide 10,12; polyamide 10,13; polyamide 10,14; polyamide 11; polyamide 12; polyamide 12,10; polyamide 12,12; polyamide 12,13; polyamide 12,14; and combinations of two or more thereof, or (ii) selected from the group consisting of polyamide 10,10; polyamide 6,6; polyamide 6; and combinations of two or more thereof, or (iii) selected from polyamide 10,10.

13. The composition of claim 7 wherein the aliphatic polyamide is selected from the group consisting of polyamide 10,10; polyamide 6,6; polyamide 6; and combinations of two or more thereof.

14. The composition of claim 11 wherein the aliphatic polyamide is polyamide 10,10.

15. The composition of claim 8 wherein the polyether-ester-amide block copolymer is

wherein A is a linear saturated aliphatic polyamide sequence having an average molecular weight of 200-15,000 and comprises or is produced from (1) a lactam or an aminocarboxylic acid having a hydrocarbon chain containing 4-14 carbon atoms or (2) an aliphatic C 6 -C 12 dicarboxylic acid and a C 6 -C 9 diamine, in the presence of a chain-limiting aliphatic dicarboxylic acid having 4-20 carbon atoms; B is a polyoxyalkylene sequence comprising or produced from a linear or branched aliphatic polyoxyalkylene glycol or a copolyether derived therefrom; and n is such a number that the block copolymer has an intrinsic viscosity of 0.8-2.05, as measured in accordance with ISO 1628-1 at 25° C.

16. The composition of claim 15 wherein the aliphatic polyamide is selected from the group consisting of polyamide 10,10; polyamide 6,6; polyamide 6; and combinations of two or more thereof.

17. The composition of claim 15 wherein the aliphatic polyamide is polyamide 10,10.

18. An article comprising a thermoplastic elastomer composition as recited in claim 1 and the article is a component part of shoes, medical devices, sporting equipment, automobiles, mechanical tools, or electronic products.

19. The article of claim 18 wherein the article is the component part of the shoe.

20. A process for preparing a thermoplastic elastomer composition of claim 1 comprising melt blending a graft-modified ethylene-olefin elastomeric copolymer, a graft-modified ethylene-propylene elastomeric copolymer, and a polyether-ester-amide block copolymer wherein each of the graft-modified ethylene-olefin elastomeric copolymer, a graft-modified ethylene-propylene elastomeric copolymer, and a polyether-ester-amide block copolymer has a grafting degree of 0.01 to 5 wt %.